Print in the Mix has the latest numbers on catalogs:

Oxbridge Communications reports the total number of catalogs in their 2008 National Directory of Catalogs is 12,230 catalogs-- a 15% increase since 2004.

There are now 1,868 online-only catalogs and 10,543 print-and-online catalogs listed in the 2008 directory.

The categories with the largest increase were Religious, Automotive, and Education. Catalogs categories that saw a decrease were Manufacturing, Computers, Crafts, and Office.