Hi there,
I was browsing the Inter.it site and I had a look at the season tickets stats (you can find them here:

http://www.inter.it/en/societa/abbonamenti99.html

OMG!!! I was absolutely speachless after seeing those figures! Napoli sold more than 60,000 season tickets in 3 different occasions and not just during the Maradona era, in the space of 20 years!! 60,000 tickets is a HUGE NUMBER! There are no records of season tickets sales since 2001/02, anyone knows how many season tickets Inter Milan has been selling during the last 3 years? And just to compare, what about AC Milan? I bet these figures are all around the 50,000 mark. Maybe season tickets used to be much cheaper in the past?