The social desirability of the tan is a modern phenomenon. The concept of having a tan without going outdoors became more and more appealing. People enjoy having a tan for innumerable reasons. Aside from cosmetic reasons of just having a good tan, people actually enjoy the therapeutic effects of tanning.
It was actually the Europeans who started tanning indoors with sunlamps. The practice of harnessing ultraviolet light as a therapeutic exercise spread in Europe, particularly in sun-deprived countries, in the 1970s. This was long before the first indoor tanning facility was established in the United Sates in the late 1970s.
Since then, the professional indoor tanning industry in the US has grown substantially in the past 30 years. According to industry estimates, it has grown into a $5 billion industry with 28 million Americans tanning indoors annually at about 25,000 tanning salons around the country.