Along with today's unemployment figures came the labor participation rate which is simply the percentage of people in the country that are working (that want to work).
The value of full employment changes with demographics (more people living longer now) and with more women joining the workforce every year. Keep in mind that 100% includes retired folks, kids, etc and since baby boomers make up a larger percentage of the population now than in the past, it's more likely that 67.5% is full employment.
That four percent (difference between 67.5 and 63.5) represents about 12 million people unemployed (4% x 300 million people in the US) which is probably not coincidentally the amount of jobs that republican presidential candidate Romney says he wants to create.
It is up to the voters in less than two months now to decide whether they believe this lack of jobs is the fault of President Obama or his situation created during the great recession.