Selling your first novel

Tobias S. Buckell has conducted a fascinating survey, asking writers if the first novel they wrote was the first they sold, how many novels did you write before selling one?

Which is quite high, I'm suprised. Also worth reading the advice collected in that post.
"I received 150 responses from a variety of authors, most of them SF/F, but thanks to Diana Peterfreund and others, a large number of Romance writers.

Of these published novelists, 65% did not break in with their first novel. 35% did."