We've made decent progress rebuilding jobs in the last four years. Since the recession ended in June 2009, the economy has added 5.5 million jobs, or about three-quarters of those lost to the Great Recession.

But the economy needs a certain number of new jobs every month just to keep up with population growth and new entrants in the labor force. That's why the unemployment rate can fall much slower than the rate at which new jobs are being created. (This is also influenced by demographic and education trends. More on that here.)

The Federal Reserve Bank of Atlanta has a nifty calculator that lets you see how long it will take for the unemployment rate to return to a given level at a given level of jobs growth. At various levels of monthly jobs growth, here's how long it will take to return to 5% unemployment:

Lots and lots and lots of time.

Keep in mind, the unemployment rate is one of the least reliable measures of the health of the labor market that we have. In the short run, we don't really know if it going up or down is a good or bad sign, since there are lots of things that can skew the results, such as people giving up looking for work. It also doesn't distinguish between the quality of jobs -- say, the level of pay, or the number of hours being offered. 

Here's another way to look at it. This chart, from the Federal Reserve and the blog Calculated Risk, shows our jobs recovery compared with other severe financial crises:

While we didn't come close to the carnage of the Great Depression in depth, it's possible that our current jobs recovery will match the 1930s in duration.

Here's one more chart from Calculated Risk, comparing this jobs recovery to recent recessions:

The deeper the downturn, the deeper the scars. And this downturn was deep. Even the most bullish forecasts put us on track for the worst jobs recovery since the Great Depression.