I put together spreadsheets with the calculations for each team in the regular season and playoffs from 54-55 through 69-70. As a bonus, I filled out the assist numbers from 54-55 through 63-64 (regular season only, B-R already has playoff numbers) since those were also missing. Here are the links:
Regular Seasons:
http://www27.zippyshare.com/v/h9Ve1NE3/file.htmlPlayoffs:
http://www27.zippyshare.com/v/OBoSUwFN/file.htmlFor a few of the earlier regular seasons, certain players have missing lines (I presume this is due entirely to trades). For those team seasons, I've used the team rebounds (times 0.878 through 67-68), team FGA, from the B-R totals. For team minutes, I just calculated 5*(nGames*48+nOT*5), going through the gamelogs.
In case anybody is interested, here are the top 10s for missing years:
Season AST% (54-55 through 63-64):
Season TRB% (54-55 through 69-70):
Playoffs TRB% (54-55 through 69-70):
There very well may be errors (some data was entered manually, and I may have missed some years when a player was traded mid-season for the leaderboards), so let me know if you find any.
Enjoy!
EDIT: Fixed the links.