According to the census bureau http://factfinder.census.gov
there were 51,234,170 owner-occupied homes with a mortgage vs. 23,852,315 without a mortgage. About 75M owner occupied homes. However, there are 126M total homes. 8.8M homes underwater represents 10% of what exactly? Total owner occupied homes is the closest. A little more clarity in the article would be great, but it definitely doesn’t seem to mean 10% of mortgaged properties. 8.8/51 is more like 16%
