In the latest jobs report from the Bureau of Labor Statistics, the unemployment rate dipped to 5.1 percent -- the lowest level in more than seven years.

But the economy added just 173,000 estimated jobs in August, another weak month that suggests the recovery isn’t accelerating. Despite the steady drop in the unemployment rate, many Americans either still haven’t found employment or aren’t looking for work.

The employment-to-population ratio tells a different story. This measure has declined over the last 15 years, a fact that’s often partially attributed to the aging of the workforce. Breaking down the employment-to-population ratio by age group, though, shows all segments of the workforce are employed at rates below pre-recession levels, with the notable exception of the oldest workers. 

Those just starting out their careers suffered particularly severe losses from 2007 through 2010, and they still haven’t recovered. Just under half of those ages 16 to 24 are currently employed, down 3 percentage points from the start of the recession in December 2007.

Older millennials, who make up the age 25 to 34 cohort, aren’t working as much, either. The employment-to-population ratio for this group has climbed over the past three years, but still remains well below pre-recession levels. 

The age 35-to-44 bracket has fared slightly better. Its ratio is still down, though, 1.9 percentage points since the start of the recession.

Workers in the age 45 to 54 group also aren’t working as often as before. The employment-to-population ratio for this group has shown no signs of improving this year and actually appears to be declining further.

The only workers employed at greater rates than before are the oldest Americans. Those ages 55 and up have historically been employed at the lowest rates of all age groups, and their rate didn’t drop as much during the recession. With more workers delaying retirement, the ratio for this group has now exceeded pre-recession levels.