No fewer than fifteen had lost one or both parents when they were children

All told, of the twenty-four individuals who became Prime Minister between 1809 and 1937, no fewer than fifteen had lost one or both parents when they were children. ... [the 1921 census] suggested that about 1 per cent of children under the age of fifteen had suffered the death of one or both parents. Yet the figure among Prime Ministers was 62 per cent. 

J. Paxman, The political animal (2002), 34-35