The number of people aged 50 and older reporting marijuana use is up from 1.9 percent to 2.9 percent from 2002 to 2008, according to surveys from the Substance Abuse and Mental Health Services Administration.

The key graph from the AP:

The drug is credited with relieving many problems of aging: aches and pains, glaucoma, macular degeneration, and so on. Patients in 14 states enjoy medical marijuana laws, but those elsewhere buy or grow the drug illegally to ease their conditions.