Year	Measure
1800	461.1
1820	461.1
1913	712.4
1950	759.9
1951	710.3
1952	734.8
1953	746.8
1954	716.7
1955	743.2
1956	763.1
1957	774.4
1958	758
1959	774.5
1960	788.7
1961	758.7
1962	767.3
1963	830.8
1964	868.3
1965	861.8
1966	888.7
1967	908.9
1968	904.6
1969	974.6
1970	961
1971	964.2
1972	950.7
1973	927.3
1974	908.3
1975	867.7
1976	852.4
1977	843.7
1978	777.4
1979	675.8
1980	638.8
1981	647.6
1982	682.3
1983	711.8
1984	630.5
1985	622
1986	603.2
1987	617.7
1988	636.8
1989	658.1
1990	661.3
1991	646.1
1992	644.2
1993	674.2
1994	693
1995	755.2
1996	799
1997	816.6
1998	830.7
1999	865.8
2000	881.2
2001	896.5
2002	927.7
2003	937.6
2004	959.7
2005	991
2006	1050
2007	1104
2008	1151
2009	1193
2010	1219
2011	1260
2012	1251
2013	1270
2014	1306
2015	1352
2016	1401
2017	1451
2018	1503