Following up on a suggestion, here's a comparison of the old-age dependency ratio for the five major global players (defined as the number of elderly per 100 working age population).
This basically shows the same conclusion as the chart from the previous item. The U.S. old-age dependency ratio goes up from about 20 to 33 over the next 45 years. That's about the same increase as India, and much smaller than China, Western Europe, and Japan.
It's also fun to take a look at the total dependency ratio (children plus elderly, compared to the working age population).
Not much change, is there?