Bricktown in Oklahoma City at dusk.

(The Center Square) – Oklahoma business owners say filling job openings remains a major concern even as national optimism in the economy is trickling upward.

“Our members say problems with the supply chain and filling jobs are making it harder for them to recover from the slowdown that began a year and a half ago,” NFIB Oklahoma Director Jerrod Shouse said in a statement.

The NFIB Small Business Optimism Index increased to 100.1 in August, up 0.4 percentage points from July, NFIB reported Tuesday. Five of 10 index components improved, four worsened, and one remained unchanged, according to NFIB. NFIB's Uncertainty Index dropped seven points to 69, its lowest level since January 2016, NFIB reported.

“As the economy moves into the fourth quarter, small business owners are losing confidence in the strength of future business conditions,” NFIB Chief Economist Bill Dunkelberg said in a statement. “The biggest problems facing small employers right now is finding enough labor to meet their demand and for many, managing supply chain disruptions.”

According to the national survey of small businesses, 50% of owners reported trouble filling job openings. That's an increase of one percentage point from July and a 48-year high for the second consecutive month, according to NFIB.

Also, the number of owners "expecting better business conditions over the next six months decreased by eight points to a net negative 28%. This indicator has declined 16 points over the past two months to its lowest reading since January 2013," NFIB reported.