Year	Measure
1800	345
1820	345
1913	366.9
1950	375.9
1951	390.8
1952	405.9
1953	422.2
1954	495.7
1955	464.9
1956	516.5
1957	537.3
1958	540.9
1959	534.3
1960	550.3
1961	574.7
1962	597.2
1963	608.9
1964	659.1
1965	692.2
1966	723.5
1967	752.6
1968	762.8
1969	786.7
1970	809.4
1971	773.8
1972	820.2
1973	819
1974	847.3
1975	859.1
1976	837.7
1977	764.7
1978	850.2
1979	852.2
1980	700.4
1981	808.8
1982	838.1
1983	752.6
1984	765.5
1985	789.2
1986	765.2
1987	736.4
1988	748
1989	734.1
1990	740.4
1991	759.7
1992	745.5
1993	737.8
1994	739.5
1995	754
1996	772.6
1997	796.7
1998	559.2
1999	590.7
2000	632.1
2001	619.4
2002	575.7
2003	560.9
2004	562.1
2005	569
2006	569.6
2007	576
2008	582.4
2009	587.6
2010	595.5
2011	614.4
2012	593.1
2013	605.3
2014	653.3
2015	673.1
2016	689.7
2017	706
2018	722.6