The population peak for Halo 4 has not surpassed 80,000 since February 8th.
Twice within the past 10 days the population peak has not surpassed 50,000. On 2/23/13, the high was 42,705 (that was a friday by the way). And 3/2/13 (a saturday) the population reached 45,221 as a peak population.
The population between those two dates (not including) averaged 64,028.
So there is your halocharts update.
Though there isn’t a way to know currently, what do you guesstimate the unique user count to be?
Feel free to comment below.