Year	Measure
1800	490.8
1820	493
1885	704.8
1886	677
1887	791
1888	760.3
1889	706.4
1890	702.9
1891	643.3
1892	703.7
1893	796.8
1894	905.2
1895	837
1896	921.1
1897	904.9
1898	928.2
1899	984.2
1900	962.2
1901	985.4
1902	1070
1903	995.3
1904	1100
1905	972.7
1906	928.9
1907	891.8
1908	973.1
1909	1010
1910	1076
1911	993.6
1912	1073
1913	1126
1914	1074
1915	1105
1916	981.4
1917	861
1918	526.7
1919	453.7
1920	455.2
1921	416.3
1922	482.8
1923	555.7
1924	703.4
1925	878.3
1926	985.3
1927	1026
1928	1078
1929	1089
1930	1138
1931	1147
1932	1128
1933	1170
1934	1276
1935	1458
1936	1556
1937	1683
1938	1677
1939	1744
1940	1670
1946	1483
1947	1647
1948	1859
1949	2029
1950	2195
1951	2166
1952	2265
1953	2322
1954	2392
1955	2549
1956	2742
1957	2747
1958	2899
1959	2814
1960	3024
1961	3140
1962	3173
1963	3054
1964	3402
1965	3551
1966	3681
1967	3803
1968	3987
1969	4005
1970	4273
1971	4343
1972	4325
1973	4644
1974	4610
1975	4460
1976	4506
1977	4452
1978	4407
1979	4236
1980	4097
1981	3994
1982	3953
1983	3939
1984	3849
1985	3749
1986	3768
1987	3686
1988	3637
1989	3577
1990	3378
1991	3007
1992	1992
1993	1644
1994	1274
1995	1098
1996	899.3
1997	898.5
1998	928.5
1999	944.1
2000	1002
2001	1081
2002	1158
2003	1250
2004	1353
2005	1413
2006	1481
2007	1563
2008	1650
2009	1679
2010	1768
2011	1854
2012	1952
2013	2046
2014	2124
2015	2205
2016	2289
2017	2377
2018	2468