Year	Age
1780	23
1860	22.8
1890	22
1900	21.9
1910	21.6
1920	21.2
1930	21.3
1940	21.5
1950	20.3
1960	20.3
1970	20.8
1980	22
1990	23.9
1991	24.1
1992	24.4
1993	24.5
1994	24.5
1995	24.5
1996	24.8
1997	25
1998	25
1999	25.1
2000	25.1
2001	25.1
2002	25.3
2003	25.3
2004	25.3
2005	25.3