Catherine Rampell finds a chart on the composition of the American population over the next four decades:
By 2030 — shown by the bars in the middle-shade of green — the entire baby boom generation will have moved into the ranks of the elderly.
This has bigger consequences than just a longer line for the early bird special. It means that a smaller portion of the population will be working, and inversely that a larger portion of the population will be depending on government services (and/or family members and meager personal savings) in order to get by.