Year	Measure
1800	487.3
1820	487.3
1913	752.8
1950	1560
1951	1591
1952	1624
1953	1655
1954	1689
1955	1723
1956	1854
1957	1780
1958	1803
1959	1963
1960	1945
1961	1893
1962	1970
1963	1862
1964	1794
1965	1870
1966	1799
1967	1697
1968	1753
1969	1812
1970	1688
1971	1754
1972	1668
1973	1482
1974	1582
1975	1729
1976	1984
1977	2214
1978	2105
1979	1818
1980	1770
1981	1749
1982	1905
1983	1821
1984	1669
1985	1504
1986	1517
1987	1516
1988	1502
1989	1583
1990	1413
1991	1466
1992	1500
1993	1503
1994	1491
1995	1496
1996	1532
1997	1641
1998	1689
1999	1767
2000	1884
2001	1943
2002	2004
2003	2088
2004	2137
2005	2261
2006	2425
2007	2636
2008	2650
2009	2660
2010	2709
2011	3198
2012	1433
2013	1855
2014	2714
2015	2805
2016	3122
2017	3520
2018	3853