What year were ABBA songs made in?

The Swedish pop group ABBA was formed in 1972 and they released their first album in 1973. Their most successful period was in the 1970s and early 1980s, during which time they released a number of hit songs, including "Dancing Queen" (1976), "Mamma Mia" (1975), and "Waterloo" (1974). Their last studio album, "The Visitors", was released in 1981, and the group officially disbanded in 1982.