Ok, so that part about the last dex update being the final one was a lie I guess. Hopefully this will be the real final count.
No overall Galar dex %s this time because it's not worth the effort imo, the trends won't change. Also, alt forms for certain legendaries won't be counted separately: The forms of Kyurem will be counted as just one mon, same for Necrozma. Meltan and Melmetal are counted as Gen 7 mons.
Kanto - 61 (55 original, 6 regional variants) (+7)
Johto - 35 (27 original, 5 cross-gen evolutions, 2 cross-gen pre-evolutions, 1 regional variant) (+1)
Hoenn - 42 (39 original, 2 regional variants, 1 cross-gen pre-evolution)
Sinnoh - 38 (23 original, 10 cross-gen evolutions, 5 cross-gen pre-evolutions)
Unova - 92 (88 original, 4 regional variants) (+7)
Kalos - 32 (31 original, 1 cross-gen evolution)
Alola - 52 (all original) (+16)
Galar - 81 (76 original, 5 cross-gen evolutions)
Total - 433
This number doesn't correspond to the currently known 435, but hey mistakes were made clearly.
Kanto - 40% of Kanto mons
Johto - 35% of Johto mons
Hoenn - 31% of Hoenn mons
Sinnoh - 35% of Sinnoh mons
Unova - 59% of Unova mons
Kalos - 45% of Kalos mons
Alola - 59% of Alola mons
Well god damn, Alola sure caught up, huh? Tied with Unova for highest dex representation! Kanto's gotten better, but still not great.