There is no comprehensive census data for the entirety of human space, however the USRE Demographics Bureau maintains an aggregate database including data from the Earth, Elora and the majority of human settlements. Albeit renewed at different intervals and depending on definitions and measurements that may not be standardized between superpowers, this database provides an interesting point of comparison.
1 - General data and Earth's supremacy
As of today, the total population of human space accounts for a little less than 6.5 billion individuals, 95% of which are organic human beings, with the remaining 5% being IA persons. The supremacy of the Earth in terms of numbers is nigh-absolute, with the homeworld accounting for slightly more than 5 billion inhabitants in total. The second most populated planet, Elora, trails behind at 150 million inhabitants, with the Traverse as a whole accounting for 200 million individuals. The vast majority of planetary settlements, aside from the two main worlds, account for anything between one million to ten thousand inhabitants. Non-planetary settlements are negligible, with less than 5% of humanity having embraced the spacer lifestyle on a permanent basis (and in fact, the most populated stations have a rather Earth-like environment). Human populations are mostly urban, albeit the rural/urban divide has stabilized at a lower level than in the industrial age (40-60 in average, with a peak at 10-90 on Elora. Note that various definitions of urban and rural spaces make this statistic unreliable.)
This total is expected to grow very slightly in the next century (see following sections).
2 - Birth and growth
The average birth rate in human space has stabilized at 2.5 children per child-bearing capable human, ensuring a very slow average natural growth. The Earth enjoys a remarkably stable demographic profile with an average of 2.1 children per child-bearing capable human (CCH), after spending the late Low Age at an average of 3.4 children per CCH. This ratio is not expected to change in the near future, albeit the potential reclamation of North America as well as certain parts of western Europe might drive natural growth on Earth slightly further in the decades to come. Emigration towards the Earth is virtually negligible.
Elora has a more dynamic population, with a ratio of 2.7 children per CCH, which is further reinforced by a very positive emigration-immigration ratio, albeit the planet is receiving less immigrants than it used to in the early years of colonisation. With Traverse emigration being highly incentivized on Elora, the planet's population is expected to plateau near or slightly above 200 million people by the end of the next century.
The other human settlements generally follow the same pattern as the Earth, with a stable population maintained at or around a local optimum in terms of resource pressure after the first colonisation wave fuelled by high natural growth of younger populations and high immigration. The few exceptions, such as Masan, have their high growth driven almost exclusively by higher than average immigration, often from Elora or the Earth.
Natural births are favoured by most human populations, with artificial uterus technology having somewhat fallen out of favour despite being widely accepted. The late Low Age ban on human cloning still holds, albeit the Irenian Enclaves practice a specific form of parthenogenesis with relative success. Statistics show that the age at which CCH have their first child skyrocketed, going from an average of 22-25 in the Low Age to 35-40.
3 - Lifespans
The average lifespan in human space is stabilized around 120 years, with the median value being exceedingly close. This average lifespan may come as somewhat of a surprise given that modern biotechs could enable humans to double or triple this life expectancy: it would however only be accessible to a small range of people, considering the material cost of expanding lives to such a degree. The general choice of favouring good quality healthcare for all over life expansion for a small elite is the main political parameter that led to this apparent "short" average life expectancy. The average human healthcare system appears rather efficient, as the mean life expectancy in good health is hovering around the 100 years mark, with organ failure due to ageing having overtaken cancer and chronic illness as the leading cause of death human space-wide.
As far as individual settlements are concerned, life expectancy is directly correlated to the habitablity of a planetary surface. The highest mean life expectancy is to be found on Elora (128 years), while the Earth has stabilized around 125 years. Less hospitable planets show way lower averages, with worlds such as Tyra or Silesia going down to 100 or even 95 years -- these statistics have to be taken with a grain of salt, however, as they are based on deaths recorded on the planet, while a lot of older people decide to emigrate to more hospitable worlds and as such aren't accounted for on their home planets. In any case, the main factor for this discrepancy seem to be premature ageing due to high radiation levels. The introduction of protective measures such as skin suits or genetic modifications isn't old enough to have had measurable effects.
4 - Age pyramids
There are three dominant age profiles among human space settlements.
The Earth shows a remarkably stable age pyramids, with age categories spread almost evenly across the population, a unique situation that it owes to the demographic dynamics of the Low Age having led to very stable birthrates maintained during the past two centuries. Space stations often have similar age profiles.
Young and dynamic settlements such as Elora have an age pyramid that favours younger populations, which is directly linked to a high birthrate as well as a prevalence of immigration, often carried out by younger persons with the intent of permanent residence.
Finally, inverted age pyramids with a deficit of younger generations are the sign of settlements that did not, or could not, attract immigrants beyond the first settlement wave, and can't sustain a high birthrate either, leading to a declining population. This is the case of a lot of scientific colonies such as Tyra or Finistelle.
5 - Sex ratio
Across all ages, the sex ratio in human space, calculated on the basis of sex assigned at birth, is strangely uneven and shows a statistically significant prevalence of women. This discrepancy is mostly concentrated in non-planetary settlements and seems to be highly correlated to exposure to cosmic rays. Furthermore, the Irenian settlements show a 70-30 sex ratio in favour of women at birth, though non-conventional reproduction methods (parthenogenesis) are responsible in this case.
6 - Family units
Fiscal census data shows that nuclear families are becoming rarer and rarer in human space, following a trend initiated during the Low Age. The average Earth family is sensibly smaller than the average Eloran family, and it general it seems that newer colonies favor bigger extended families which is directly correlated to the fact that these populations often come from the same colonisation ship or fleet.
7 - Mobility
In average, 35% of all human beings have travelled into space during their lifespan, with 18% having lived on another habitable planet for more than a week. These statistics are highly region-dependent. Terrans are the least mobile people in human space, with only 20% of them having been to space and 7% on another world, albeit mobility inside the Earth is much higher. On the other hand, inhabitants of the Traverse are much more mobile, with 75% of them having travelled in space and 57% having lived on another world.
Interestingly enough, residential mobility is at its highest between planets, and especially planets with similar gravity (ecosystems and climate don't seem to have much impact on the choice of permanent residence). Mobility between planets and space stations is rarer, with spacer populations being mostly endogenous.
The point-to-point nature of faster-than-light travel via geometry drive drove human expansion in the Milky Way in a very specific way, with vast swathes of stars being left mostly unexplored in-between points of interest. Human space is best understood as an archipelago, where a total of about two hundred settled systems are scattered across half the Milky Way, separated by seemingly endless three-dimensional seas of stars, interstellar gas clouds and void. Note that even inside the bubbles of settled space unknown or barely charted systems might still exist: humanity's knowledge of space is eminently fragmented.
The symbolic and demographic heart of human space is a subset of about seventy settled systems centred around the solar system and the Earth: Communal Space, accounting for more than 80% of humankind's total population. Communal Space also incorporates more isolated stations, such as the wandering stations of the Irenian Enclave in the Pleiades and the Witch Head Nebula.
The second-largest settled region is a cluster of G and F-class stars named the Traverse, sitting roughly 500 lightyears away from the solar system and shrouded by the dark region of a nebula. The Traverse is centred around Elora, a "super-habitable" world which houses the most well-developed planetary society aside from the Earth. The Traverse accounts for twenty to thirty settled systems, depending on the metric being used. Though it follows the same cooperative system as Communal Space, this region is controlled by more elaborate polities known as qiths.
Within the same distance of the Sun, but in the galactic south can be found a similar but smaller bubble of a dozen settled systems named after the binary habitable system of Smyrnia. This region doesn't have a single political system and is instead in a "flux state" of highly dynamic anarcho-syndicalist jurisdictions. Smyrnia neighbours - at a stellar scale - a similar region, the Serene Sea which owes its name to the fact that it finds itself at the middle of a vast expanse of stellar remnants. Its fifteen-odd settlements are the main theatre of humankind's complex relationship with the Sequence, a relic of the Milky Way's past which should have perhaps remained buried in time.
Not much further away but across the inter-arm void is an even smaller settled region centred around a concentration of waterworlds referred to as the Okean Bubble. It is the place of the first contact with an ancient, complex and eminently bored aquatic species, the Vriij. Located at the edge of a globular cluster above the plane, its dozen systems are watched upon by scientific organisations and Communal cooperatives.
Aside from these settled regions exist the Isolae, or islands in the sky, that is to say, completely isolated systems that were discovered and selected by deep space exploration ships due to their remarkable features. Tyra, the first isola, is located in the central bulge of the Milky Way. This formerly habitable world was sterilized by a gamma burst several million years ago and is considered a planet-sized laboratory. It is a notable stop on the Neutron Pathway, a well-charted translation route plunging deep towards the heart of the galaxy.
The second isola, Mundis, is probably the most well-developed of them all. This peculiar habitable world orbits a gas giant and bears the marks of climate and geological engineering of alien origin, making it a prime site for the study of the galactic past. Shrouded in mystery, Mundis is under the control of the Mundian Ekumen, a deep space commune existing in complete isolation. Mundis can be reached through the Via Mereisa and is also the beginning of the Laniakea Run.
The third and so far last isola is the single most isolated settlement in the galaxy. Finistelle lies high above the Milky Way and at the very edge of the galactic disk, which gave it its name - "Star's End", quite literally. While Finistelle often appears as a completely gratuitous endeavour, the Starmoth Initiative considers it as a prime observation site with an unparalleled vantage point on the galaxy. It can be reached through the gruelling, complex route codenamed Star's End Crossing.
Aside from these isolae are deep space stations that mark the smallest isolated settlements - not even inhabited planets but constellations of stations, either free-floating or orbiting a star. Lovelace Point is made of seven stations orbiting Sagittarius A* and its surrounding stars, at the end of the Neutron Pathway. Gondwana Port is an anchor point for mobile stations and long-range ships exploring the ruins in the galactic west. The Lighthouse is a deep space station in the Sagittarius arm watching over a star cluster, at the end of the Sagittarius Arm Run. The most elusive, and perhaps most isolated station is Station Zero, hanging in the void, at the heart of a vast network of ruined megastructures linked to the Sequence. At the end of the famous Laniakea Run, Station Zero is the crown jewel of the Starmoth Initiative.