The first six locations have a distance of 0.00 miles. After that it jumps to 6.2 miles and higher. Plotting these points on a map makes a person think that Seattle doesn't have any businesses in it; it shows a few results by the city center and many results miles away.
Looking at the underlying Local Search query reveals the problem:
The first few results have a distance of 0.00 miles, but then you immediately jump up to the farther distances of 6.2 miles and higher. YQL sorts these results correctly, of course, but the underlying data is so whacked out that even the YQL query ends up being worthless.
Increasing the number of results grabbed doesn't help. Even if I grab from local.search(0,200) the closest business is 6.12 miles away.
Searching for a more specific address, like "724 Pine Street, Seattle, WA 98101" doesn't help either. Even when I grab 200 addresses the nearest business is 0.2 miles away, and after that 5.19 miles away: