How many are still on the road?

[moparrob]

I'm trying to determine the number of Porsches utilizing CIS (Bosch K-Jetronic) fuel injection that are still in service. These would be all 911 models from late 1973 through 1983.

Does anyone happen to know how I could obtain that information?

I am in the process of developing a product to improve the induction system on those particular vehicles and am trying to determine the potential depth of the market.

Thanks in advance for any assistance you may provide.