Unemployment rate versus employment to population ratio

Given the tepid new jobs numbers out today, I got interested in private sector versus public sector job growth over the past several years. I went to the Bureau of Labor Statistics website, hoping to get a handle on to what degree the storyline of recovery is different for the two sectors. I wasn't able to find any obvious numbers on that question, but while I was playing around with their data tool, I found something else interesting.

This is a plot of the unemployment rate over the past 6+ years. It topped out at 10.0 in October 2009 and has been falling fairly steadily since and is now around 8%.

This is a plot of the ratio of employed persons to the total population. In October 2009, when the unemployment rate topped out, the employment/population ratio (as a percent) was 58.5. However, while the unemployment rate has declined, the ratio of employed to population has remained static. Since October 2009 it has fluctuated between 58.7 and 58.2, and is currently at 58.4. So the only reason the unemployment rate has gone down (and Republicans have been saying this for a year or more) is because people have stopped identifying themselves as job seekers. I can think of several plausible scenarios in which that might happen:

1) Older workers who planned to retire in a few years but who have become unemployed choose to retire early rather than look for a job.
2) Students choose to pursue further education, delaying entry into the job market.
3) Dual-income households shrink to single-income households.
4) Discouraged unemployed workers decide to depend on welfare and charity rather than work.
5) Employees shift to unreported employment.

There may be other explanations that I'm not thinking of, but it seems to me that all five of these have significant downsides and only a couple of possible upsides. (1) probably means that people aren't sufficiently prepared for retirement financially, and will put an even greater strain on the Medicare/SS system. (2) means that a large pool of job seekers will hit the market at a future point, pushing the unemployment rate statistic back up. (3) means families survive on decreased income. (4) and (5) represent failures of the state, either to encourage productivity among the populace or to fairly distribute taxation. On the other hand (2) means a better educated workforce, which I think is generally a good thing (although not always) and (3) potentially means greater availability of parents to children.

I guess I'm wondering whether this divergence between the two numbers is temporary (in which case the media focus on the unemployment rate leads to a wrong impression of the true state of employment), or whether there's been a permanent shift in the percentage of the US population participating in the job market (in which case I'm unsure, but generally have a negative feeling about, the long-term implications).