WASHINGTON -- Unemployment rates fell in fewer than half of U.S. states, evidence that slower hiring has affected many parts of the country.

The unemployment rates in 24 states dropped, the Labor Department said Friday. Rates rose in 13 states and Washington, D.C, and were flat in 13. That's a significant decline from April, when 39 states reported falling unemployment rates.

And only 22 states reported a net gain in jobs in May, while 27 states lost jobs. That's much worse than April, when 42 states gained jobs.

The changing trend in state unemployment rates reflect a weaker economy that has been hampered by high gas prices and lower factory output. Nationally, employers added a net gain of only 54,000 jobs in May, compared to an average of 220,000 per month in the previous three months. The U.S. unemployment rate ticked up to 9.1 percent.

California, New York and Pennsylvania reported large job losses, partly reversing gains earlier this year. California said employers cut 29,200 jobs last month, with big losses in professional and business services, which includes accounting, engineering, and temporary services. The construction sector also lost jobs.

New York said employers cut 24,700 jobs and Pennsylvania reported a drop of 14,200 jobs.

But those drops follow large gains in April and don't represent a longer-term trend, said Marissa DiNatale, a regional economist at Moody's Analytics. New York added 53,000 jobs in April, and Pennsylvania added 23,900.

"The actual picture of what's going on is somewhere in the middle" of the April and May figures, she said.

Florida, meanwhile, reported the biggest job gains. Employers in the Sunshine State added a net total of 28,000 positions. The state's unemployment rate dropped for the fifth straight month to 10.6 percent. The gains were mostly in education and health services and in leisure and hospitality, which includes amusement parks, hotels and restaurants.

The gains reflect some pickup in tourism that is boosting the state's theme parks and resorts, said Sean Snaith, an economist at the University of Central Florida.

While the state is adding jobs and unemployment is falling, the improvement is "moving at the speed of a glacier," Snaith said. He doesn't expect hiring to really accelerate until next year.

Earlier this year economists had expected much stronger job growth. But a payroll tax cut enacted in December hasn't spurred the additional consumer spending that many economists expected. Americans have had to spend most of the extra money to pay higher prices for food and gas.

The economy grew by only 1.8 percent in the January-March period, a sharp slowdown from the 3.1 percent annual pace in the October-December quarter.

Nevada had the highest unemployment rate among the states, at 12.1 percent, though that was down sharply from April's 12.5 percent. California had the second-highest rate, at 11.7 percent, down from 11.8, followed by Rhode Island at 10.9 percent, which was unchanged.

North Dakota reported the lowest unemployment rate, at 3.2 percent, followed by Nebraska at 4.1 percent and New Hampshire and South Dakota at 4.8 percent.