200 000 theorems every year

"Stalislaw Ulam estimates that mathematicians publish 200 000 theorems every year. A number of these are subsequently contradicted or otherwise disallowed, others are thrown into doubt, and most are ignored. Only a tiny fraction come to be understood and believed by any sizeable group of mathematicians."

cité dans
Richard A. De Millon
Richard J. Lipton et Alan J. Perlis
CACM, May 79, Vol 22, Number 3, p. 271-280