Year	Measure
1800	364
1820	364
1913	304
1950	282.9
1951	294.6
1952	298.8
1953	306
1954	317.5
1955	322.5
1956	329.2
1957	336
1958	342.6
1959	346.2
1960	364.7
1961	364.1
1962	411.8
1963	446.1
1964	472.3
1965	472.4
1966	459.7
1967	498.6
1968	485.6
1969	481.6
1970	481
1971	426.3
1972	496.6
1973	612
1974	634.3
1975	569.2
1976	648.4
1977	745.4
1978	839.4
1979	765.9
1980	800.5
1981	788.8
1982	797.3
1983	710.9
1984	752.1
1985	759
1986	755
1987	774
1988	851.8
1989	922.6
1990	940.3
1991	956
1992	977.5
1993	991.6
1994	967.1
1995	1068
1996	1149
1997	1186
1998	1137
1999	1153
2000	1187
2001	1221
2002	1275
2003	1311
2004	1370
2005	1415
2006	1482
2007	1550
2008	1625
2009	1699
2010	1801
2011	1900
2012	1970
2013	2035
2014	2094
2015	2163
2016	2242
2017	2325
2018	2413