Calculated Risk digs into the numbers a bit. Here's the employment-population ratio:

and here's a graph of those who are working part-time when they'd prefer to work full-time:

During the previous two recessions, denoted by the light blue vertical stripe, the employment-population ratio did not start to move up until two years after the recession ended. If the current trend continues, we'll be looking at a much quicker bounce-back. Of course, it's also a bounce-back from a much deeper trough.