Year	Measure
1800	674.7
1820	674.7
1913	818.4
1950	883.7
1951	881
1952	879.6
1953	879.7
1954	915.6
1955	822.8
1956	868.2
1957	860.7
1958	943.1
1959	844.5
1960	934.5
1961	1005
1962	1072
1963	1136
1964	1198
1965	1255
1966	1328
1967	1385
1968	1440
1969	1496
1970	1551
1971	1597
1972	1533
1973	1460
1974	1460
1975	1531
1976	1612
1977	1738
1978	1796
1979	1948
1980	2164
1981	1530
1982	1890
1983	1688
1984	1514
1985	1601
1986	1584
1987	1517
1988	1508
1989	1499
1990	1497
1991	1459
1992	1429
1993	1407
1994	1400
1995	1383
1996	1365
1997	1339
1998	1327
1999	1321
2000	1321
2001	1332
2002	1353
2003	1396
2004	1436
2005	1460
2006	1620
2007	1627
2008	1747
2009	1787
2010	1835
2011	1890
2012	1928
2013	1974
2014	2051
2015	2771
2016	4008
2017	4355
2018	4353