Did the networks(I mean ALL of them,ABC,CBS,NBC,FOX,the CW)begin airing closing credits the way it is now?In other words,when did they stop airing full screen credits on all network series?Was it in the 1990's or the 2000's?

It had to be during the 90s. I found a clip on Youtube from 1998 and NBC was already using split credits.

http://www.youtube.com/watch?v=KE88p99MbGk