Year	Measure
1800	419.2
1820	419.2
1870	419.1
1913	568.9
1950	524
1951	533.4
1952	545.9
1953	573.1
1954	579.1
1955	584.5
1956	604.3
1957	597.9
1958	624.6
1959	634.8
1960	640.8
1961	647.1
1962	652.4
1963	657.2
1964	661.4
1965	665.6
1966	699.9
1967	676.4
1968	668.5
1969	685.3
1970	689.7
1971	668.2
1972	674.8
1973	657
1974	683
1975	677.2
1976	690.4
1977	694.1
1978	707
1979	705.9
1980	672.3
1981	655.4
1982	718.4
1983	679.9
1984	727
1985	752.6
1986	765.2
1987	775.6
1988	815.8
1989	813.8
1990	852.7
1991	884.4
1992	897.7
1993	909
1994	959.5
1995	968.6
1996	995.5
1997	1011
1998	1005
1999	1014
2000	1055
2001	1085
2002	1057
2003	1065
2004	1079
2005	1081
2006	1078
2007	1093
2008	1139
2009	1169
2010	1204
2011	1229
2012	1264
2013	1282
2014	1312
2015	1345
2016	1379
2017	1415
2018	1451