The Blitz: Estimated Luftwaffe sorties stats

Reference 1: Luftflotte 2 sorties, Luftflotte 3 sorties and Major attacks.

Reference 2: October 1940, November 1940, December 1940, January 1941, February 1941, March 1941, April 1941 and May 1941.

Source: http://en.wikipedia.org/wiki/The_Blitz