Year	Measure
1800	512.9
1820	512.9
1913	792.5
1950	832.3
1951	986.6
1952	853.5
1953	809.4
1954	878.6
1955	918.4
1956	941.5
1957	944.4
1958	926.8
1959	921.3
1960	928.1
1961	878.2
1962	897
1963	912.9
1964	970.1
1965	950.2
1966	1038
1967	1057
1968	1097
1969	1127
1970	1170
1971	1203
1972	1222
1973	1241
1974	1255
1975	1205
1976	1207
1977	1268
1978	1329
1979	1325
1980	1344
1981	1322
1982	1348
1983	1306
1984	1280
1985	1287
1986	1331
1987	1362
1988	1396
1989	1414
1990	1429
1991	1403
1992	1342
1993	1306
1994	1310
1995	1336
1996	1361
1997	1360
1998	1355
1999	1347
2000	1318
2001	1304
2002	1288
2003	1291
2004	1317
2005	1359
2006	1403
2007	1457
2008	1436
2009	1432
2010	1471
2011	1492
2012	1518
2013	1561
2014	1612
2015	1666
2016	1728
2017	1778
2018	1835