Year	Measure
1800	364.5
1820	364.5
1913	563.1
1950	1061
1951	1104
1952	1147
1953	1193
1954	1239
1955	1181
1956	1289
1957	1312
1958	1246
1959	1468
1960	1541
1961	1506
1962	1453
1963	1448
1964	1599
1965	1842
1966	1695
1967	1777
1968	1753
1969	1695
1970	1722
1971	1673
1972	1773
1973	1704
1974	1789
1975	1671
1976	1719
1977	1589
1978	1553
1979	1461
1980	1462
1981	1503
1982	1409
1983	1329
1984	1279
1985	1259
1986	1224
1987	1213
1988	1250
1989	1226
1990	1300
1991	1265
1992	1211
1993	1261
1994	1068
1995	1018
1996	1061
1997	1071
1998	1027
1999	1026
2000	1036
2001	1060
2002	1072
2003	1105
2004	1141
2005	1175
2006	1219
2007	1263
2008	1303
2009	1353
2010	1420
2011	1481
2012	1551
2013	1632
2014	1721
2015	1809
2016	1905
2017	1998
2018	2101