[legion]

It's more common than you'd think. 65 was originally chosen as the "retirement age" for social security because it was the average life expectancy of a male at the time. In other words, it was designed so that roughly half the people that "paid into the system" would never see a dime and would fund the retirements of the other half that actually lived past retirement.

Another interesting statistic is that those that retire at 55 on average end up living much longer than those that retire at 65. So those that retire at 55 need to earn a lot more in their roughly 35 working years than those that retire at 65 in their roughly 45 working years.