Year	Measure
1800	871.6
1820	871.6
1875	1885
1876	1867
1877	2002
1878	1840
1879	1863
1880	1770
1881	1743
1882	2141
1883	2334
1884	2426
1885	2770
1886	2695
1887	2795
1888	3157
1889	3365
1890	2983
1891	2730
1892	3176
1893	3267
1894	3665
1895	3949
1896	4246
1897	3317
1898	3499
1899	4011
1900	3420
1901	3612
1902	3437
1903	3831
1904	4131
1905	4562
1906	4580
1907	4464
1908	4694
1909	4708
1910	4832
1911	4726
1912	4923
1913	4778
1914	4092
1915	3950
1916	3768
1917	3398
1918	3962
1919	4039
1920	4263
1921	4242
1922	4452
1923	4807
1924	5036
1925	4861
1926	4962
1927	5178
1928	5357
1929	5457
1930	5081
1931	4634
1932	4394
1933	4518
1934	4790
1935	4909
1936	4873
1937	5150
1938	5085
1939	5200
1940	5202
1941	5393
1942	5368
1943	5248
1944	5758
1945	5483
1946	5845
1947	6360
1948	6560
1949	6323
1950	6253
1951	6362
1952	5911
1953	6108
1954	6243
1955	6567
1956	6630
1957	6857
1958	7158
1959	6575
1960	6985
1961	7367
1962	7133
1963	6853
1964	7453
1965	8022
1966	7956
1967	8053
1968	8284
1969	8871
1970	9212
1971	9408
1972	9443
1973	9633
1974	9990
1975	9766
1976	9612
1977	10080
1978	9603
1979	10120
1980	10130
1981	9422
1982	8998
1983	9239
1984	9302
1985	8526
1986	9027
1987	9140
1988	8846
1989	8108
1990	7847
1991	8576
1992	9308
1993	9742
1994	10210
1995	9808
1996	10250
1997	10970
1998	11270
1999	10770
2000	10570
2001	9993
2002	8798
2003	9481
2004	10230
2005	11060
2006	11870
2007	12750
2008	13460
2009	13420
2010	14490
2011	15600
2012	15710
2013	15970
2014	16340
2015	16640
2016	16950
2017	17260
2018	17580