Officially, no. Roughly sorta, ffxiah.com could give a rough idea of active accounts in a given period. However, that can't really differentiate between mules and mains. As has been the case for a while, Asura tends to be the most active NA server for the moment, thanks to reddit and continued suggestion over time in similar threads here/elsewhere.
Dunno about peak times, but a "/sea all" on Sylph yields ~450-500 players during random times throughout the day.
Seems to me a lot of people hang out in Mhaura but I do see people randomly in other places, especially Gustav Tunnel which is mildly annoying, lol.
I woulda thought that with all the new areas in the game, people wouldn't bother much, but being that it is the highest-level Grounds Tome, I suppose that's why they're there. Just wish SE would have added more similar areas with Lv100+ mobs that feature GoV Tomes than just that one.
From what I know, Asura has the highest population, with 1100ish during peak hours. The remaining servers vary from 200-600. SE offers server transfers, if you find yourself coming up short or feeling lonely when you log in.