Real people

It turns up in 27 of their lyrics, across almost the whole of the band's recording life, 1963 to 1970. Nothing before 'Roll Over Beethoven' uses it, and nothing after 'Dig It', with The Beatles (The White Album) leaning on it hardest, ten of its 30 tracks. The peak is 1967 and 1968, sixteen of the 27, 'Julia' the last of them, and it dwindles to six after that. John takes the lead on thirteen of the 27, against eight for Paul, with George on four. On 'Taxman', the lyrics name Harold Wilson and Edward Heath, the two main UK political leaders of the era. On 'Revolution 9' it is George Martin, Alistair Taylor (uncredited spoken intro).