Job gains in 2015 were strong, but ...

The U.S. economy may not have fared as well in 2015 as job growth numbers would indicate.

Total employment in the U.S. rose by 2.45 million, marking the third straight year with more than 2 million jobs gained, according to data from the Bureau of Labor Statistics. The year ended on a high note, adding 292,000 jobs in December, easily beating consensus estimates.

The last time the U.S. economy added more than 2 million jobs three years in a row was between 1997 and 1999.

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However, many jobs created in 2015 in the U.S. came from low-paying sectors, particularly retail, professional services and food services.

In fact, 1.16 million — or 47.2 percent — of the jobs added by the U.S. economy came from those three sectors, leading to wages rising at a slow pace. Hourly wages climbed 1.94 percent in 2015 and have not risen by 2 percent or more since 2012, BLS data show.

Also weighing on wage growth is stalling jobs expansion within manufacturing, once considered one of the hallmarks of the U.S. economy.

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Manufacturing jobs grew by just 13,000 in 2015, remaining essentially flat, as the sector struggled to stay afloat. The sector contracted in November and December and had been slowing down since June, according to the Institute of Supply Management.

"Bottom line, while the headline print [for December manufacturing] was a bit weaker than expected, the softness wasn't that much different than seen in November. That said, it does reinforce the challenges currently being faced by the manufacturing sector which is arguably in a recession for reasons we all know (stronger dollar, economic weakness in China and the rest of Asia)," Peter Boockvar, chief market analyst at The Lindsey Group, said in a note.

Steve Blitz, chief economist at ITG Investment research, told CNBC "that is likely the area of weakest jobs growth this year. ... There is nothing today that suggests that is going to change."

Blitz also noted that financial services, another high-paying sector, would likely see little growth in jobs. "I'm not particularly optimistic about high-wage jobs, particularly in the financial sector, because a lot of those jobs are tied to mortgages," he said.

Another high-paying sector weighing on wage growth in the U.S. was oil and gas extraction, which saw the number of jobs decline by nearly 15,000 in 2015, or about 7.5 percent. Last year also marked the first one-year jobs contraction within the sector since 2009, when positions fell by about 10,000, or 6 percent.

The oil and gas business has been hit by a sharp decline in crude prices, which has been triggered by massive oversupply within the market.

The slowdown in jobs growth within oil, as well as in other high-paying sectors, raises questions as to whether the Fed will be able to justify raising rates four times this year, Blitz said. "I don't see that kind of data."