Year	Measure
1800	454.3
1820	454.3
1913	497.4
1950	515.7
1951	529.7
1952	543.3
1953	557
1954	571.4
1955	586.4
1956	602
1957	617.2
1958	633.9
1959	649.7
1960	661.9
1961	684.8
1962	722.5
1963	708.6
1964	719.6
1965	741
1966	737.8
1967	794.8
1968	810.8
1969	817.4
1970	809.7
1971	831.9
1972	854.7
1973	798.6
1974	772.3
1975	727.9
1976	709.4
1977	743.4
1978	811.6
1979	800.9
1980	794.8
1981	809.7
1982	807.2
1983	778.1
1984	770.5
1985	848.8
1986	955.4
1987	912.1
1988	957.9
1989	917.4
1990	880.2
1991	938.1
1992	931.8
1993	895.9
1994	879
1995	889.9
1996	929.2
1997	946.3
1998	978.6
1999	1010
2000	1001
2001	1030
2002	1038
2003	1081
2004	1097
2005	1140
2006	1176
2007	1189
2008	1221
2009	1220
2010	1278
2011	1292
2012	1364
2013	1427
2014	1492
2015	1560
2016	1630
2017	1701
2018	1774