The oldest of the 78 million Americans born during the post-World War II baby boom generation are turning 65 this year, while the share of the population older than 85 is growing even faster. The flood of elderly Americans is putting severe financial stress on programs that benefit older citizens. The number of people covered under Medicare will increase by more than 30 million over the next 20 years. So far, congressional proposals for constraining Medicare spending have encountered stiff resistance. But economists say the country's deficits will become unmanageable if entitlement programs aren't scaled back. The United States is not aging as rapidly as other developed countries and will continue to have a growing population of working-age people. But as longevity and spending on health care increase, many seniors will outlive their retirement savings.