Historians agree that the middle classes not only professed high personal moral standards, but actually followed them. There is a debate whether the working classes followed suit. Moralists in the late 19th century such as Henry Mayhew decried the slums for their supposed high levels of cohabitation without marriage and illegitimate births. However new research using computerized matching of data files shows that the rates of cohabitation were quite low—under 5%—for the working class and the poor. By contrast, in 21st-century Britain nearly half of all children are born outside marriage, and nine in ten newlyweds have been cohabitating.