This list covers only the post-war awards to general fiction for adult readers: one annual winner from 1950 except two undifferentiated winners 1973 to 1975, dual hardcover and paperback winners 1980 to 1983.
For 1980 to 1983 this list covers the paired "Fiction (hardcover)" and "Fiction (paperback)" awards in that order. Hard and paper editions were distinguished only in these four years; none of the paperback winners were original; in their first editions all had been losing finalists in 1979 or 1981.
From 1980 to 1985 there was also one award for first novel or first work of fiction and in 1980 there were five more awards for mystery, western, and science fiction. None of those are covered here.
Source: Wikipedia