Each of the different lines on the graph are based on estimates from different historical demographers. Their names are shown in the key.

The graph illustrates the ‘demographic collapse' that occurred after the Black Death, meaning that England had a much lower population during the fourteenth century.

That population only began to recover again in the sixteenth century. It is most likely that the Black Death and repeated subsequent outbreaks of bubonic plague helped to keep population growth at a low level (almost zero), although the plague epidemics in the sixteenth and seventeenth centuries did not prevent demographic recovery or economic growth.