This graph shows the number of registered model years 1965 – 1969 Porsche 912’s (coupé’s and targa) per model year with the FACTORY-DELIVERED TIRES (confirmed  by official documents like the kardex, certificates,  …… but, unfortunally I don’t have official documents from every 912 ever made/registered. This graph is just to give you an idea. 

Note: Using exact numbers in the graph will give you for example 1 (ONE!) Veith Pirelli, but that is not enough to show 1% as you can see)