Sorry that this took so long to find.
Out of "Beekeeping" by John Eckert and Frank Shaw (1960):
They reported a work by Farrar (1931) in comparing colony strength by
counting the average number of flights out of the colony each minute.
3 pound package 15 bees flying per minute
5 pound package 48.5 bees flying per minute
3.5 pound overwintered colony 64.5 bees flying per minute
7 pound overwintered colony 128.3 bees flying per minute
Hope this answers your question of hive population.
John van Horn
first year, two hives (1 package, 1 swarm), no honey yet :-{