Year	Measure
1800	387.8
1820	387.8
1913	530.6
1967	1305
1968	1325
1969	1246
1970	1267
1971	1252
1972	865
1973	929.9
1974	1132
1975	962.5
1976	1058
1977	1170
1978	1231
1979	1485
1980	1348
1981	1477
1982	1467
1983	1613
1984	1579
1985	1542
1986	1792
1987	1784
1988	1797
1989	1890
1990	1870
1991	1927
1992	2110
1993	2132
1994	2262
1995	2379
1996	2350
1997	2252
1998	2230
1999	2159
2000	1802
2001	1597
2002	1530
2003	1588
2004	1672
2005	1712
2006	1740
2007	1808
2008	1892
2009	1761
2010	1821
2011	1964
2012	2024
2013	2059
2014	2089
2015	2120
2016	2148
2017	2177
2018	2202