The older 78 format continued to be mass-produced alongside the newer formats using new materials until about 1960 in the U.S., and in a few countries, such as India (where some Beatles recordings were issued on 78), into the 1960s. For example, Columbia Records' last reissue of Frank Sinatra songs on 78 rpm records was an album called Young at Heart, issued November 1, 1954. As late as the 1970s, some children's records were released at the 78 rpm speed. In the United Kingdom, the 78 rpm single lasted longer than in the United States and the 45 rpm took longer to become popular. The 78 rpm was overtaken in popularity by the 45 rpm in the late 1950s, as teenagers became increasingly affluent.

Answer this question, if possible (if impossible, reply "unanswerable"): What was the last country to phase out the 78 rpm?
United Kingdom