BISMARCK, N.D. (AP) — North Dakota counties that produce either coal or crude oil held seven of the top 10 spots in a statewide survey of average annual wages.
The counties that have lignite mining, power plants or oil have some of the best-paid workers in the state, Job Service North Dakota research analyst Michael Ziesch said Wednesday.
‘‘Those are the powerful, high-paying jobs,’’ he said.
Job Service figures show coal-rich Oliver County in west-central North Dakota retook first place in the study of average annual wages in 2009 among North Dakota’s 53 counties. Sparsely populated Slope County, which had held the top spot because of a spike in oil development, slid to No. 3.
Statewide, the average annual wage last year was listed at $35,970, up from $35,075 in 2008 and $33,086 in 2007. Fourteen counties topped the statewide average last year, the same as 2008.
Oliver County, home to BNI Coal’s Center Mine and Minnkota Power Cooperative’s Milton R. Young Station, ranked first last year. The average annual wage rose to $60,202 from $50,403 in 2008.
The report lists Oliver County’s average number of workers at 827 last year, up from 679 in 2008.
Job Service figures show Oliver County had ranked at the top of North Dakota wage surveys since at least 1993 but was surpassed in 2008 by Slope County, in the state’s southwest corner. Ziesch said oil activity in Slope County since about 2004 has lifted it from near the bottom in average wages.
Slope County is among the nation’s least populated counties. Ziesch said the county’s average number of workers dropped from 206 in 2008 to 132 last year, as some drill rig workers likely moved on to other areas of the state’s oil patch.
Ziesch said the small work forces in Slope and Oliver counties make the rankings volatile.
‘‘Add a few high-paid employees and you can push the average,’’ he said.
Mercer County, north of Oliver County, ranked No. 2 last year with an average annual wage of $52,384, the report said. It ranked fourth in 2008 with an average salary of $47,772. Its average number of workers jumped from 4,848 in 2008 to 5,252 last year, Ziesch said.
Mercer County is home to Basin Electric Power Cooperative’s Leland Olds Station near Stanton. That plant and the Milton R. Young Station in Oliver County are both undergoing multiyear, $400 million upgrades, said Steve Van Dyke, a spokesman for Bismarck-based Partners for Affordable Energy, a coalition that supports coal-based electricity.