A solid back-to-school shopping season gave a modest boost to August retail sales, according to the National Retail Federation (NRF). Excluding automobiles, gas stations and restaurants, August retail sales increased 0.2% seasonally adjusted month-to-month and 3.8% unadjusted year-over-year.

"The retail industry continues to demonstrate its strength and resiliency during this fragile economic time," NRF President and CEO Matthew Shay said. "However consumers and retail companies continue to face many questions and challenges, from stubbornly high unemployment and stagnant incomes to depressed housing prices and the looming fiscal cliff, all playing into overall economic uncertainty and declining consumer confidence."

August retail sales showed total retail and food services sales, which include non-general merchandise categories such as automobiles, gasoline stations, and restaurants, increased 0.9% seasonally adjusted month-to-month and 4.7% unadjusted year-over-year, according to the U.S. Department of Commerce.

"While retailers continue to witness sustained sales growth, consumers remain cautious about their discretionary expenditures," NRF Chief Economist Jack Kleinhenz said. "Consumers have carried much of the growth during the economic recovery, despite high food and gas costs. Though the economy isn't backsliding, growth continues to be a sore point."

Sporting goods, hobby, book and music stores' sales were flat seasonally adjusted month-to-month, but increased 6.6% unadjusted year-over-year, NRF said. Clothing and clothing accessories stores' sales decreased 0.1% seasonally adjusted month-to-month, but increased 7.8% unadjusted year-over-year.