Jared Bernstein emphasizes it:
[A]s the figure [above] shows, for recipients age 65 and up on, Social Security is about two-thirds of their income and that share grows with age—for the old-elderly, it’s closer to 70% of their income. Other data show that for a third of those over 65, Social Security accounts for at least 90% of their income.
Derek Thompson points out that Social Security isn't the only important program. In response, Bernstein notes that "poverty among the elderly goes from 9% with Social Security benefits to 45% without them."
The Dish 