Sales of existing homes in the U.S. rose 2.3 percent in July, as low mortgage rates, rising rent and some job creation led to a modest rebound, a trade group said. The National Association of Realtors said sales increased to a seasonally adjusted annual rate of 4.47 million from 4.37 million in June. Economists polled by MarketWatch had anticipated a 4.5 million rate. Compared with July 2011, sales climbed 10.4 percent, the 13th straight month with a year-on-year gain.