The Social Security time bomb continues to approach detonation. Each working adult is supporting more and more retirees. The ratio of workers to retirees dropped from 12 to 1 in 1950 to 4 to 1 in 1990. The ratio is projected to be 2.2 per retiree in 2050. And Americans are living longer after they start collecting Social Security checks. A 65-year-old is expected to live about 10 years longer in 2040 than he did in 1940. In their new book, Retooling Social Security for the 21st Century, Urban Institute scholars Eugene Steuerle and Jon Bakija suggest pushing up the retirement age from its scheduled 67 in 2032 to 70 and then "indexing" it if life expectancies continue to increase.