Small business owners' optimism is growing even as they hold to a lukewarm view of the economy, according to a survey released Wednesday.

Nearly three-quarters of the owners questioned by the advocacy group National Small Business Association said they're confident about the future of their businesses, up from two-thirds in a similar survey taken in December. Sixty-three percent see growth opportunities in the coming year or are already seeing growth. They're not very worried about rising interest rates--34 percent see higher rates as a problem, down from 36 percent six months ago.

That increased optimism has more owners planning to hire. One-third said they expect their payrolls to increase in the next year, up from 30 percent in the previous survey. And half say they expect to give workers raises, up from 46 percent.

The results are in line with the findings of other surveys in recent months. Owners have faith in their companies, but they're not as upbeat about the economy. They're gradually increasing their staffs.

Owners' view of the economy in the latest NSBA survey was little changed from December. Twenty-seven percent anticipate that the economy will grow in the next year, unchanged, and 55 percent say it will remain flat, down slightly from 56 percent.

They remain anxious about the economy's impact on their companies. Economic uncertainty was mentioned most often as a significant challenge to the growth and survival of businesses; 55 percent of the owners cited it.

But the further away the country gets from the 2008 credit crunch, the easier it is for small businesses to borrow. Nearly three-quarters of the owners said they're able to obtain adequate financing, up from 70 percent in December. And the number of owners reporting they were getting easier loan terms edged up to 6 percent from 5 percent.

The survey, which questioned 1,252 small business owners online, was conducted in late July and early August.