By Joseph Coughlin, MIT AgeLab
In the last century, the American lifespan has increased beyond any historical precedent. In 1900, the average life expectancy was 47 years old. Today it is around 78, and for certain demographics — such as women with a college degree — it is closer to 85. Younger generations may be in line for even bigger longevity dividends. It’s possible that an American born in 2007 can expect to live past 100.