I would say here it was about 1/3 each to Deere, IH, and Gleaner with the oddball MF or Ford here and there.  Deere had the most consistent dealer.  Looking at the link to old IH dealers someone posted the other day I think there were 6 ownership changes from 1950-84.  Local AC dealer was gone by the time I was born in '81 for sure and probably 10 years sooner but a dealer 45 minutes or so away was really good and when you needed parts you just went and got them, no need to call and check even for something like a final drive.  Cousins ran Gleaners exclusively till '79 when they traded the last K for a 6620.  In '77 they had traded the other K for a M, which would have been a Deere if availability weren't an issue, which was the same reason they ended up with a 1486 instead of a 4640 in '78.  The Gleaner stayed through the '88 crop and in '89 was replaced with the first Maximizer sold locally, a 9400.  That was the last Gleaner they owned and the last I remember in the neighborhood.  They still had a 4wd Allis that was troublesome and it was the end of their AC equipment.  At one time they were 100% AC.  Deere was a consistent dealership, closer for parts, had better resale, and the equipment was very reliable.  IH had its loyal customers so there were lots of 615s and 715s sold then a good many Axial Flows.  If Gleaner had kept up better they probably would have stuck with orange stuff more and if that 1486 hadn't been a lemon and complete disappointment then red may have gotten very serious looks going forward.  Green came through when given a chance and didn't disappoint, starting with 4020s, and ended up being the only thing considered when it was time to buy.  Dad farmed with them but had grown up green and never strayed, and being 61 probably never will.