THOUSANDS OF SLOT CARS ?

Last week end, I was wondering how many different slot cars models have been manufactured since the 60's ? I haven't find any precise figures, but I am sur that it would be very difficult and expansive to buy all of them. Because, when you combine the hundreds of models issued in Europe by Scalextric alone, plus the Fly's and Jouef hundreds, the SCX dozens, etc., you finally obtain easily a huge figure. Do anybody have any precise numbers in mind ?