Is heavyweight really less competitive today?

[pugilisticspecialist]

Can any of the editors please tell me how many active heavyweights there were on 01/01/1900, 01/01/1910 etc. all the way up to 01/01/2010.

By "active" I'm mean those who fought in the 365 days previous to the 01/01. I'd like to know both how many active 200 lb + fighters as well as how many 175 lb + fighters there were on each date, if this would be possible.