The mood among the nation's small-business owners picked up this month, rebounding from a 22-month low in June, Discover reported this week.

In a monthly survey of 1,000 owners nationwide, 23 percent said they felt the U.S. economy was improving in August, the highest percentage in a year, according to the Riverwoods, Ill.-based credit card firm. Sixty percent said the economy was getting worse, down from 71 percent in July, while 30 percent said business conditions were getting better, up from 28 percent.

Despite the improved outlook, a growing number of owners reported cash-flow problems  over the last 90 days, the survey found.

"There is still a great amount of caution out there," Ryan Scully, director of Discover's business credit card, said in a statement.