Generations: The Real Differences Between Gen Z, Millennials, Gen X, Boomers, and Silents—and What They Mean for America's Future

by Jean M. Twenge

In a 1969 Gallup poll, only 1 out of 25 American adults said they had ever tried marijuana, but that number rose to 1 out of 8 in 1973 and 1 out of 4 in 1977.