During the 2029-30 Period the ASC suffered losses ON-SCREEN** (establishing a minimum) of:
47 Fighters (37 Slyphid, 5 Phantom, 5 from Carpenter's Tokagawa)
40 AGAC
22 Roc Shuttles
09 VHT (all 15th ATAC, though IINM there is at least one other ATAC unit in this theatre)
09 Battloids (Assort type)
08 ASC Cruisers (generically bunched together, I am treating them as equal to a Tri-Star)
04 Pegasus Shuttle
04 Logans (Note Marie trashed her Logan a few times, but is not counted here)
02 Infantry (there are also crew members injured/killed on ship but I am not counting them to avoid double counting with the loss of a ship/vehicle)
Plus the Communities of Newton & Manville (had ASC forces present), Moon Base (ASC not the civilian ALUCE, mentioned in Ep38), ASC HQ (though a portion could have been evacuated), Suburban Base in Sector 3 ("Danger Zone"), and some armored vehicles (IIRC).
By 2044 the UEEF suffered losses on-Screen** (establishing a minimum) or other canon losses in the 85Ep series (not TSC) of:
24 Alpha-class (some may or may not have been docked to a Beta, but as the Beta is usually unmanned, includes Shadow)
13 Garfish
12 Cyclones (mostly VR-052s)
04 Horizon-T (no idea what was in the cargo pods: troops or just hardware/logistics and I'm not speculating)
03 Ikazuchi
Plus the Tokagawa Grant Commanded in Prelude and Point K (6000 troops, was there more than 1 Point X base, Invasion Video Game had a Point L, if that is the case A-L would mean 12 bases, if they are identical to Point K in population...), the UEEF fleet loses in TSC (sorry I don't have numbers, but some of them might be double counted in Ep84-5 so best to avoid them), Edwards rogue group, and the 10th MD (Implied strength is 14 Garfish and 3 Ikazuchi in opening panel of Invasion comic for a population of ~6400 people). The UEEF would also suffer losses against the Regent and possibly other races they came into conflict with (mentioned in AotSC about the Angel-Class and colonization).
In terms of population we know the ASC could staff a Tokagawa Cruiser (I'm assuming this is distinct from Grant's) that appears to have survive the 2RW without loss (on-screen), x1 ASC Desert Base, Monument City's Aerospace Base, and the UEEF could staff the SDF-3 and eventually SDF-4 along with Space Station Liberty (evacuated aboard the Ark Angel putting a cap on size), ALUCE Moon Base staff, Tirol Base, at least 1x ASC Naval Base seen in NG saga and countless mecha/ships/vehicles seen but not destroyed on-screen but that can not be otherwise uniquely identified between shots to prevent double counting that would have to be alive in 2029.
There is also a deep space colonization effort that required the construction of at least 14 Angel-Class vessels (converted into Neutron-S missiles), of which we have no real data on but we know exist (85ep had 7N-S missiles in one shot, TSC shows at least that many in another shot still at SSL in dry dock).
Using in order of preference RT.com Infopedia, AotSC, and then 2E PB RPG for crew counts of these platforms this means in terms of minimum population size of both entities in 2029 would be:
ASC 15,501
UEEF 29,644 (some of which are children in this time frame, some might also be micronized Zentreadi in UEEF service, includes Point K along with Grant's Tok and the SDF-3/4).
Grand Minimum Total: 45,145
We also know CIVILIANS exist in 2029 on Earth in large numbers (a few hundred are captured alone to be reprocessed as Bioroid Pilots per dialogue, massive numbers are also seen during evacuations in the last episode or two).
So what kind of (Average) Population Growth Rate* did humans experience between 2012 and 2029 and then to 2044 (this also doesn't factor in premature loss of life due to war, the most major event occurring in 2029-30):
-@01.10% in 2029 the population would be 84,308 and in 2044 it would be 99,342
-@02.10% in 2029 the population would be 99,663 and in 2044 it would be 136,120
-@04.20% in 2029 the population would be 140,880 and in 2044 it would be 261,135
-@08.67% in 2029 the population would be 287,501 and in 2044 it would be 1,000,000
-@11.05% in 2029 the population would be 415,828 and in 2044 it would be 2,000,000 (TSC dialogue implied minimum)
-@15.48% in 2029 the population would be 808,347 and in 2044 it would be 7,000,000
An average human population growth rate of 1.1% (current rate) or even 2.1% (highest on record set in 1968 per Wikipedia) do not work because of all the unaccounted for personnel in 2029 IMHO (even a pessimistic simple doubling of the minimum size for those two factions causes issues and this is before even considering the colonization effort). In order to get population numbers that come close to working (with what is stated in TSC if we use it) and give wiggle room the average population growth rate in these periods has to be over 4x higher than any period in recorded human history which seems unlikely to be the case. Given that the casualties of the 2RW are not accounted for in progression from 2029 to 2044, that would also mean you need even more people in 2029 if they had been subtracted out to meet TSC's stated population.
I think we can rule out Zentreadi/Tirolian survivors (as a major factor) contributing to population growth in this period since mixed individuals are apparently rare (making them a minor factor at best) and therefore not counted. The 2E RPG (unlike the 1E, Novels, and current cannon) does allow for it beyond the Sterlings, but gives no real percentage of the overall population or other numbers who are mixed race, just that they exist (and how they break down internally by genetic donor castes from each group).
So how do we explain the population size issue in 2044? The only options I can see (in universe) would be:
1. There are more than 70,000 human survivors contributing to the human population growth (the 1E RPG had 30% world survivor rate, or 300million per billion survived, the 2E RPG and Novels also go with basic premise though not necessarily the number 1E used AFAIK). In order to get 2 milion people in 2044 (ignoring war losses) would require a total survivor population (minimum) x20 what Leonard stated. This is achievable I think (treating Leonard's statement with some room for interpretation), the RoD did not strike everywhere (per Global Map in Ep27 @ approx 6:37-40) and we know NYC survived intact due to NG (if even ~1/8 of the city's population survived it would provide enough people) and did not suffer a direct hit. NYC would still have to contend with secondary effects, but if they could get help it would go a long way in explaining Earth's population issue on screen and what the math/history says is possible versus Leonard's and the officer in TSC dialogue statement.
2. There was cloning of Terran humans, though nothing in RT establishes they did this or even contemplated it. The technology would have to come from the Zentreadi, either adapting the Sizing Chamber technology found on their ships or the Factory Satellite that was captured.
3. There was a historically unprecedented population growth rate that was sustained/averaged-out-to for this entire period. This seems difficult to believe, at least at the rates required.
4. Some combination of the above
*
**From an old screen counting attempt I did years ago, I may have missed things it is possible. Nor do I dispute that losses occurred off screen, these numbers should be taken as the minimum.