Somewhere I read that Basho wrote about 2000 haiku in his life of which 100 or so are considered excellent, and of which he believed there were maybe ten that truly hit the mark. This is a tough ratio but perhaps holds a realistic perspective for us all. Excellent haiku craft requires tireless resolve to keep at it despite the misses and bunches of weaker attempts, with hope that out of the effort will surely come some keepers, and, if we are lucky, serendipity may provide an opportunity to create a haiku that will stand the test of time.
--Tom Clausen, "A Haiku Way of Life"