I have also heard of 5000 RHD and 3600 LHD, but this could as well be 6000 RHD and 2600 LHD.

In Y2K there were 300 registered in Germany, in jan 04 a mere 71 was left....

About the numbers left, apart from all the reasons RSKieron mentions, a lot got damaged because of race and rallye programs. In Germany they had a special S1 rallye cup, so that must have cost a lot of cars.