Our wizard marketing department at Paragon used multiple sources to calculate a close estimate of how many housing units sell in SF each year, and of what type (condo, SFH, etc.).
As logic would dictate, homes turn over less often than condos/TICs. Overall, about 5.5% of existing houses, condos, co-ops and TICs sell each year, including both MLS and non-MLS sales. This does not include new-construction condos, and those number can vary greatly by year.