MAE ANDERSONNEW YORK (AP) â¿¿ Americans shoppers proved resilient in July, driving a key sales figure up at retailers across the country, despite persistent worry about jobs and the global economy. Results came in better than expected for many retailers, helped by hot weather and summer clearance sales, an encouraging sign as the back-to-school season, the second-biggest shopping season behind the holidays, kicks off. A preliminary tally by the International Council of Shopping Centers of 20 retailers found revenue in stores open at least a year rose 4.6 percent in July, higher than the 3 percent to 3.5 percent the ICSC expected. Summer clothing purchases drove the increase. The sales figure rose 9.2 percent for clothing, the largest monthly increase since April 2011, according to the ICSC. "Hot weather and summer clearance, coupled with some newness in stores in the back half of the month, is leading to a nice upside heading into back-to-school," said Ken Perkins, president of Retail Metrics, a research firm. He said colored denim is a key fashion trend that is new in stores and attracting customers. "Retailers were pretty aggressive with promotions, trying to clear out merchandise." Analysts had expected modest gains in the month, which was the hottest July in 50 years, according to research firm Planalytics. But Americans shrugged off high unemployment and the bumpy global economy to hit the mall, spending more than expected. "I think the U.S. consumer surprised a lot of people," said Chris Donnelly, global industry managing director for retail at Accenture. "When you look at income, the savings rate, and unemployment, there's still a lot of cause for pessimism, but the U.S. consumer is amazingly resilient and has spurts of spending." Other measurements of consumer strength have been mixed. On Tuesday, The Conference Board reported that its Consumer Confidence Index rose for the first time in five months. Still, that measure remains at historic lows, and is not expected to improve significantly until hiring picks up substantially. And a separate Commerce Department report Tuesday showed Americans spent no more in June than May, even though their income grew by 0.5 percent.