How many people can St. Peter's Basilica hold?

On 8th December 2004, my husband and I attended the Celebration of the Immaculate Conception at St Peter's Basilica, Rome. My ticket, which I still have, was number 09322.

There is a reference on the Time.com website about 8000 people having tickets for a service there in 1983.

http://www.time.com/time/magazine/article/0,9171,875183,00.html == For centuries, until recently, St. Peter's was the biggest church structure in the world. It's maximum capacity is listed at 60,000 people.