reddit | In case anyone is wondering (from the article)alternative work arrangements – defined as temporary help agency workers, on-call workers, contract workers, and independent contractors or freelancers.
The point is, companies are not hiring employees. They are filling roles with subcontractors from temp agencies (which have been exploding in size). These temporary workers have no job security, often no benefits (having to buy health insurance out of their pay for example), no way in hell they are getting stuff like stock options. And on average they get paid substantially less than the employees they replace.
US population in 2006 was ~300M and in 2014 about ~320M. People above 65 years of age was 12.4% and 14.4% respectively - which comes to 37.2M and 46.08M old people respectively. (Source http://data.worldbank.org/indicator/SP.POP.65UP.TO.ZS/countries/US?display=graph)
US labor figures for age 65+ group seems to be 5.325M in 2006 and 7.971M in 2014 (Source http://data.bls.gov/timeseries/LNU02000097)
So the employment rate of 65+ group has gone from 14.31% in 2006 to 17.29% in 2014.
The old people's 'no-option-but-have-to-continue-working' rate has gone up by 3% from 2006 to 2014. Maybe people are finding it more difficult to retire in this hard-to-save economy and maybe this will only worsen as we move more away from the baby-boomer generation and move further deep into this bubble economy.
EDIT relevant data - life expectancy in 2006 was 77.9 and peaked at 78.8 in 2012.