Put that in your pipe and smoke it. A recent analysis of national survey data shows that the number of middle-aged and older marijuana users is steadily increasing. Around 9 percent of Americans aged 50-64 used cannabis in 2015 and 2016, up from 7 percent in 2013, and users over the age of 65 more than doubled during that time. Nearly half of the older group also said they started using the drug after the age of 21. Experts say increasing access to medical marijuana has contributed to the trend.