Year	Age
1800	19
1930	17.65
1940	18.21
1941	18.21
1942	18.34
1943	18.41
1944	18.46
1945	18.6
1946	18.69
1947	18.53
1948	18.59
1949	18.57
1950	18.68
1955	19.07
1960	19.57
1965	19.74
1970	20.19
1975	21.74
1979	23.12
1981	22.82
1982	22.62
2005	23.31