12.7% of boys from birth live to be 65 in the U.S.

Living Longer
However, this fact is misleading in some respects because this only applies to men from age zero. However, if we apply the second part which is: "If men live to be 21 in the U.S. then 54% of them can expect to see 65 as of 1990 statistics. And  the average life expectancy of a male who survives to be 21 in 1990 was 80.3 years of age which means he will be able (on average) to collect Social Security until that age or longer.

Note: The "Living Longer" word button above is a longer article on this same subject of longevity in the U.S. if you are interested.