Year	Measure
1800	422
1820	422
1885	569
1886	546.1
1887	637.6
1888	612.4
1889	568.5
1890	565.3
1891	517
1892	565.1
1893	639.4
1894	725.9
1895	670.6
1896	737.5
1897	724
1898	742.1
1899	786.3
1900	768.2
1901	786.1
1902	852.9
1903	792.8
1904	875.4
1905	773.6
1906	738.2
1907	708.3
1908	772.3
1909	800.6
1910	852.9
1911	786.8
1912	848.7
1913	890.2
1914	848.8
1915	872.2
1916	870
1917	679.8
1918	531.1
1919	415
1920	397.1
1921	380
1922	425.8
1923	477.1
1924	534.6
1925	599
1926	671.1
1927	752
1928	842.6
1929	851.1
1930	888.1
1931	894.8
1932	879.6
1933	911.2
1934	993.3
1935	1134
1936	1209
1937	1307
1938	1302
1939	1352
1940	1294
1946	1144
1947	1269
1948	1432
1949	1562
1950	1689
1951	1665
1952	1740
1953	1782
1954	1835
1955	1954
1956	2100
1957	2102
1958	2217
1959	2150
1960	2309
1961	2398
1962	2423
1963	2332
1964	2597
1965	2711
1966	2882
1967	3030
1968	3134
1969	3254
1970	3614
1971	3670
1972	3741
1973	3950
1974	4264
1975	4544
1976	4788
1977	5086
1978	5430
1979	5792
1980	6014
1981	6284
1982	6360
1983	6580
1984	6877
1985	7151
1986	6500
1987	6515
1988	6816
1989	6298
1990	5375
1991	4278
1992	2393
1993	1725
1994	1577
1995	1648
1996	1862
1997	2086
1998	2176
1999	2264
2000	2332
2001	2473
2002	2638
2003	2961
2004	3167
2005	3505
2006	3764
2007	4235
2008	4346
2009	4178
2010	4389
2011	4669
2012	4943
2013	5213
2014	5511
2015	5842
2016	6209
2017	6614
2018	7044