The December jobs report may not be as good as it seems.

Economists let out a collective cheer on Friday when the December jobs numbers were reported. That’s because the number of jobs created during the month was higher than expected, all at a time when many are worried the weakness in the global economy might drag the U.S. down as well. Employers added 292,000 workers to their payrolls in December, significantly more than the 211,000 economists had predicted.

The problem: When measured against a year ago, rather than the expectations for this month, December’s jobs report doesn’t look nearly as good. In fact, job growth slowed in 2015, the first annual dip in the employment market since the Great Recession. In December 2014, employment increased by 329,000. And in 2015, employers added a collective 2.7 million jobs, 466,000 fewer jobs than in 2014, when employment increased by 3.1 million.

So, is the American economy slowing, or is the slowing job growth simply an indication that the job market has recovered and adding more jobs is getting tougher? After all, the unemployment rate hit 5% in October, down from 10% in late 2009, and it has stayed at that level ever since. Eventually, job gains will slow down even if the economy is still healthy. Put another way, is the economy nearing full employment or are job gains once again falling short?

To answer that question, you can compare the job gains of the current economy recovery to others. Since the end of 2009, employment has increased by 13.6 million jobs. In the six years following the early 1980s recession, the number of workers with jobs rose by 18.1 million. The 1990s rebound saw a slower increase of 16.2 million jobs in the same period. But it was still a larger overall gain than what we are currently experiencing.

Job recoveries have weakened for several possible reasons. There’s the falling labor force participation rate, which many have attributed to retiring baby boomers. But the American population is bigger than what it was two decades ago, and in the wake of a pretty severe recession, you would expect the U.S. to be adding more jobs now.

This suggests that the economy is indeed slowing, and it’s not just that hiring has maxed out. Indeed, the workforce is still growing, up 466,00 in December alone. That likely means the participation rate is not stuck and will rise, meaning that there will be more people looking for work in the next year, and that there is likely more slack in the job market. So while December’s jobs report may seem like a green light for the Federal Reserve to go ahead and continue to raise interest rates, it’s more like a blinking yellow. Caution ahead.