If we're talking JUST GN's, not TR's as a whole, here are the #'s produced by year:
1982- 215 (only 16 believed to be turbocharged)
1984- 2000
1985- 2102
1986- 5512
1987- 20,193
With all the other TR's in the mix, the total # of turbo cars for each year are as follows:
1983- 3732
1984- 5204
1985- 4204
1986- 7896
1987- 27590
Rarest GN- 1982- only 215 produced
Rarest Turbo GN- 1984- only 2000 produced
Rarest Turbo Regal(non GNX)- 1987 Regal Limited- only 1035 produced
2nd Rarest TR(non GNX)- 1987 WE4 Turbo T only 1547 produced
Quickest stock TR- 1987 GNX
Quickest stock non GNX TR- 1987 WE4 Turbo T
Quickest stock GN-1987
As to how many are actually left.....Who knows. My head starts to hurt when I think about things like that.
All the above info was from gnttype.org