The number of people seeking unemployment assistance in May in the U.S. extractive industries was up by nearly 5 percentage points year-on-year, federal data show.

The Bureau of Labor Statistics reported an unemployment rate of 7.2 percent in May for the mining, quarrying, and oil and gas extraction sectors. That's up from the 2.6 percent reported in May 2014.

Of all non-farm sectors surveyed by the bureau, the extractive industries were the lone standout in terms of job losses year-on-year.

"Total non-farm payroll employment increased by 280,000 in May, and the unemployment rate was essentially unchanged at 5.5 percent," Friday's report read.

A report from this week from career transition firm Challenger, Grey & Christmas finds the employment climate in the oil and gas sector may be stabilizing as May job losses were far less than those reported in April.

"Exploration and extraction companies responded quickly to the drop in prices, but they are likely to be careful about cutting too deeply, as they will need workers on hand when demand inevitably increases," John Challenger, the firm's chief executive officer, said in a statement. "Unless, there is another severe drop in the price of oil, we probably will not see another surge in oil-related job cuts this year."

Oil prices are down about 40 percent year-on-year. Prices have since recovered from early 2015 lows, however, amid signs of slow, but steady, global economic recovery.

A January report from Challenger, Grey and Christmas, Inc., found the economies in states thriving on the nation's oil boom may experience a "steep decline" in employment across all sectors.