three-speed hub gearing system, often imported from England, first became popular in the United States in the late 1950s. These comfortable, practical bicycles usually offered generator-powered headlamps, safety reflectors, kickstands, and frame-mounted tire pumps. In the United Kingdom, like the rest of Europe, cycling was seen as less of a hobby, and lightweight but durable bikes had been preferred for decades. In the United States, the sports roadster was imported after World War II, and was known as the "English racer". It quickly became popular with adult cyclists seeking an alternative to the traditional youth-oriented cruiser bicycle. While the English racer was no racing bike, it was faster and better for climbing hills than the cruiser, thanks to its lighter weight, tall wheels, narrow tires, and internally geared rear hubs. In the late 1950s, U.S. manufacturers such as Schwinn began producing their own "lightweight" version of the English racer. In the late 1960s, Americans' increasing consciousness of the value of exercise and later the advantage of energy efficient transportation led to the American bike boom of the 1970s. Annual U.S. sales of adult bicycles doubled between 1960 and 1970, and doubled again between 1971 and 1975, the peak years of the adult cycling boom in the United States, eventually reaching nearly 17 million units. Most of these sales were to new cyclists, who overwhelmingly preferred models imitating popular European derailleur-equipped racing bikesvariously called sports models, sport/tourers, or simply ten-speedsto the older roadsters with hub gears which remained much the same as they had been since the 1930s. These lighter bicycles, long used by serious cyclists and by racers, featured dropped handlebars, narrow tires, derailleur gears, five to fifteen speeds, and a narrow 'racing' type saddle. By 1980, racing and sport/touring derailleur bikes dominated the market in North America. Fatbike was invented for off-road usage in 1980. Europe In Britain, the utility roadster declined noticeably in popularity during the early 1970s, as a boom in recreational cycling caused manufacturers to concentrate on lightweight (), affordable derailleur sport bikes, actually slightly-modified versions of the racing bicycle of the era. In the early 1980s, Swedish company Itera invented a new type of bicycle, made entirely of plastic. It was a commercial failure. In the 1980s, U.K. cyclists began to shift from road-only bicycles to all-terrain models such as the mountain bike. The mountain bike's sturdy frame and load-carrying ability gave it additional versatility