In 2007, 3rd Q, 16% of subprime adjustable rate mortgage were either 90 day delinquent or going into foreclosure, and that triples the rate in 2005. There were about 1.3 million properties. In that year, the average home price was $260,000, that is about $33.8 billion in the 3rd Q alone. Where did you get 仅是增加了18亿坏账? I suggest you at least read the English wiki about the problem before writing anything. Motivated reasoning doesn't help you.