Colorado’s economy rose at the fourth-fastest rate of any state on an inflation-adjusted basis last year — after California, Oregon and Texas — according to a report Tuesday from the U.S. Bureau of Economic Analysis.

Colorado had a 3.6 percent increase in “real” state GDP last year, down from the 4.1 percent growth rate measured in 2014 but better than the 2.4 percent increase for all states.

“Colorado still fared very well in real GDP growth in 2015,” said Brian Lewandowski, an economist at the University of Colorado.

Colorado’s real state GDP increase in the fourth quarter, which is the way the federal government measures it, also remained the fourth-best, even as Oregon, Texas and California dropped back.

But there’s more to the story. Economic activity can be measured two ways: in real or inflation-adjusted terms, and in raw or nominal terms. In 2014, that didn’t make much of a difference. Colorado had the third-fastest rate of GDP growth either way.

Not so in 2015. Colorado’s nominal GDP, which doesn’t take inflation into account, rose 3.1 percent last year. That was strong enough to rank only 30th among states, says Natalie Mullis, chief economist at the Colorado Legislative Council.

“If you look at it that way, Colorado doesn’t look as good, although Colorado is faring much better than other energy states,” she said.

North Dakota went from first for state GDP growth in 2014 in both real and nominal terms to dead last in real terms and 49th in nominal. Alaska, Wyoming, Oklahoma and Texas were other bottom dwellers in nominal terms.

The big drop in oil and gas prices cut deeply into the income that petroleum producers generated in 2015 compared with 2014, even if they found a way to keep up overall production levels. Coal and metal miners, farmers, ranchers and other commodity producers also faced deflation.

In Colorado, natural resource and mining output fell 30.9 percent last year when measured in raw dollars. And that has cost jobs in certain parts of the state.

Weld County, the top county in the country for its rate of job growth in 2013 and 2014, ranked fifth from the bottom out of 324 large U.S. counties in 2015 with a 3.1 percent decline in non-farm jobs, according to the U.S. Bureau of Labor Statistics.

As 2015 came to the end, agriculture, utilities, mining, transportation, private education and government were detracting from state economic output, according to the real GDP counts.

On the flip side, the northern Front Range’s robust real estate market made the strongest contribution to increasing real GDP, followed by information, construction, manufacturing and professional and business services.

Mullis said the nominal numbers show a continued deterioration as 2015 wore on, something that the real numbers reported by the BEA masked.

Comparing the fourth quarter of 2014 to the same period in 2013, Colorado had the fourth-best increase in nominal GDP of any state. By the fourth quarter of 2015, its quarter-over-quarter nominal GDP growth rate had slipped to 37th.