More banks failed in the United States this year than in any year since 1992, during the savings-and-loan crisis, according to the Federal Deposit Insurance Corp. Amid high unemployment, a struggling economy and a still-devastated real estate market, the nation is closing out the year with 157 bank failures, up from 140 in 2009. As recently as 2006, before the bubble burst, there were none. Now, there are more on the horizon. The FDIC’s list of “problem” banks – those whose weaknesses “threaten their continued financial viability”- stood at 860 as of Sept. 30, the highest since 1993. Historically, about a fifth of banks on the watch list end up failing.