Average retirement age: 65

Number of U.S. workers 65 and older: 6.83 million

Number of U.S. workers 70 and older: 3 million

Life expectancy for 65-year-old man: 82

Life expectancy for a 65-year-old woman: 85

One in four Americans say they'll work until they're at least 80.

Four in 10 workers say they retired earlier than planned.

Six in 10 workers ages 55 or older have less than $100,000 saved for retirement.

Sources: U.S. Census Bureau, Centers for Disease Control, Wells Fargo, Employee Benefits Research Institute