Propelled by solid business at clothing and electronics stores, growth in September retail sales offered a promising outlook for the holiday months ahead, according to the National Retail Federation (NRF).

Excluding automobiles, gas stations and restaurants, September retail sales increased 0.4% seasonally adjusted month-to-month and 2.1% unadjusted year-over-year. This follows August retail sales, which increased 0.2% seasonally adjusted month-to-month and 3.8% unadjusted year-over-year.

"In spite of the uncertainty and unease surrounding our nation's high unemployment and long-term fiscal challenges, consumers continue to spend and shop," NRF President and CEO Matthew Shay said. "Robust back-to-school spending combined with a series of new, technology-led product launches certainly helped retailers in September. The American consumer is holding their own in this economic environment, but the question remains for how long?"

September sales showed total retail and food services sales, which includes non-general merchandise categories such as automobiles, stations, and restaurants, increased 1.1% seasonally adjusted month-to-month and 5.4% unadjusted year-over-year, according to the U.S. Department of Commerce.

"With recent data painting a more optimistic view of consumer confidence, we can finally see some light at the end of the tunnel," NRF Chief Economist Jack Kleinhenz said. "While the latest retail sales data indicates continued improvement for the economy, increasing gas prices and the looming fiscal cliff still pose serious challenges to the momentum we've seen in consumer spending."

Bookstore, music store, sporting goods and hobby stores' sales increased 0.8% seasonally adjusted month-to-month and 3.9% unadjusted year-over-year, NRF said. Clothing and clothing accessories stores' sales increased 0.6% seasonally adjusted month-to-month and 3.6% unadjusted year-over-year.