Google has failed me, or I have failed Google. In either case I
cannot seem to find any statistics on the number of Apple II clones
sold in the US or worldwide. I had a clone, as did most of my
friends. It was economics.
I ask this because according to Wikipedia, "During the Commodore 64's
lifetime, sales totalled 17 million units, making it the best-selling
single personal computer model of all time." (Yes totaled was spelled
wrong in the article--fixed now :-). And according to Wikipedia Apple
II sales sans the IIgs were less than 5 million. But the number of
clones are not taken into consideration. AFAIK the C64 was not cloned
(correct me here).