I ran the numbers for both and the numbers were 1 or 2% higher each year through 2003. In 2004, the numbers jumped to 24%, then to 29% in 2005 and 28% in 2006 so far.
I would hypothesize this is due to 2 factors. The first is the addition of developers new construction into the MLS which didnt really start until 2005 (i.e. they didnt need us before then to sell their product). The second and likely much more significant factor is investors/flippers. With appreciation gone, recent investors are getting out as they are not covering costs in contrast to long time investors that have positive cash flow. Also, the flippers hit the condo market much harder than SFH because it was cheaper to buy and easier to care for. I guess this is yet another reason that Condos will get hit harder.