Optimism among small business owners weakened in September as firms continued to struggle finding the right talent amid a tight labor market, according to a survey from the National Federation of Independent Business.

The NFIB small business optimism index eased to 107.9 last month from an all-time high of 108.8 in August. The Econoday consensus estimate was for a reading of 108.0.

Of the survey respondents, 61% said they were hiring or trying to hire, down 1 point from August. Owners continued to report hiring woes, with 22% of respondents citing the difficulty of finding qualified workers as their single most important business problem.

A net 37% of firms reported raising overall pay to attract more workers, surpassing the record net 35% reading in May. "Small business owners continue to face labor force challenges but are increasing compensation to keep up," said NFIB Chief Economist Bill Dunkelberg.

A net 8% of owners reported higher nominal sales in the past three months, while the net percent of owners expecting higher real sales volumes rose to 29%. The net percent of owners planning to build inventories fell to 3% in September from a net 10% in the prior month.