In 1952, the Queen congratulated 255 people on their hundredth birthdays and 1135 couples on their sixtieth wedding anniversaries. By 1996, these numbers had risen to 5218 and 11,688, respectively. Semilogarithmic plots, normalized to constant numbers of births and marriages, show steady exponential rises in the number of centenarians with a doubling time of 11 years, and of diamond weddings with a doubling time of 19 years. An alternative plot of the numbers of those reaching a hundred between 1910 and 1990, based on registers of births and deaths and normalized to constant births, shows an annual rise of only 1% from 1910 to 1946, followed by a steady exponential rise with a doubling time of 12 years, closely matching that of 11 years derived from the Queen's figures. The exponential rise in the number of those born from 1846 onwards living to a hundred precedes by many years the general rise in the expectation of life at birth and the general drop in mortality from infectious diseases, but it coincides with the beginning of a steady rise in real wages. Another important factor may be improved medical treatment at old age from 1946 onwards.
展开▼
