World's 65 and older population to triple by 2050

The world's 65-and-older population will triple by mid-century to make up 1 in 6 people.

U.S. Census estimates released Tuesday show the number of senior citizens has already increased 23 percent since 2000 to 516 million, more than double the growth rate for the general population. The fastest-growing age group, seniors now comprise just under 8 percent of the world's 6.8 …