In 1950s America, smoking was cool, with movie stars like James Dean and Marlene Dietrich making it look stylish. Cigarette companies even claimed smoking was good for you, with one famous advertisement claiming, "More doctors smoke Camels than any other cigarette." But things started to change in 1951, when a British scientist found a link between smoking and lung cancer. Today, things look very different, and smoking in the US is at its lowest level in 80 years. In the 1950s, nearly half of US adults smoked. Now, according to a poll from Gallup, only 11% of American adults say they've smoked in the past week — half the number from 10 years ago. One reason is that more people now see smoking as bad for you, with 79% of Americans agreeing that cigarettes are very harmful. Another major reason is that fewer young adults are smoking. Young adults used to smoke the most out of any age group, but now they're the least likely to smoke. In the early 2000s, 35% of US adults under 30 smoked, but today, it's just 6%. Instead, it's the older generation that are the biggest smokers these days, with 18% of adults aged 50 to 64 saying they smoke. Although smoking may be declining, vaping is becoming more popular. Vaping, or using e-cigarettes, is less common than smoking, with just 7% of adults saying they vape. But vaping is more popular with young adults, and nearly 1 in 5 of American adults under 30 vape. And if they keep vaping into middle age — and if young people today start vaping as they grow up — vaping might soon become more common than smoking. Health experts say even though vaping is less harmful than smoking, it's best to avoid both.