Which Beatles duo was responsible for composing most of their songs?

Lennon-McCartney was the songwriting partnership between English musicians John Lennon (1940–1980) and Paul McCartney (born 1942) of the Beatles. It is widely considered one of the greatest, best-known, and most successful musical collaborations ever by records sold, with the Beatles selling over 600 million records worldwide as of 2004. Between 5 October 1962 and 8 May 1970, the partnership published approximately 180 jointly credited songs, of which the vast majority were recorded by the Beatles, forming the bulk of their catalog.

Source: Wikipedia