Year	Measure
1800	801.9
1820	828.9
1870	1416
1871	1441
1872	1436
1873	1501
1874	1547
1875	1540
1876	1515
1877	1547
1878	1605
1879	1698
1880	1799
1881	1803
1882	1609
1883	1547
1884	1566
1885	1599
1886	1605
1887	1577
1888	1632
1889	1702
1890	1774
1891	1816
1892	1932
1893	2058
1894	2080
1895	2035
1896	2076
1897	2062
1898	2000
1899	1998
1900	2074
1901	2164
1902	2223
1903	2223
1904	2226
1905	2378
1906	2431
1907	2525
1908	2505
1909	2476
1910	2652
1911	2764
1912	2783
1913	2909
1914	2844
1915	2790
1916	2460
1917	2406
1918	2265
1919	2622
1920	2210
1921	2429
1922	2725
1923	2577
1924	2745
1925	2739
1926	2948
1927	3237
1928	3360
1929	3552
1930	3926
1931	3864
1932	3688
1933	4067
1934	4095
1935	3944
1936	3935
1937	4083
1938	4083
1939	4538
1940	4774
1941	5411
1942	6238
1943	6575
1944	7112
1945	7563
1946	7759
1947	8432
1948	8439
1949	8116
1950	7750
1951	7469
1952	7268
1953	8211
1954	8801
1955	9459
1956	9489
1957	9244
1958	9790
1959	9769
1960	9890
1961	9724
1962	10350
1963	11220
1964	12130
1965	12790
1966	13700
1967	13320
1968	12440
1969	12660
1970	13530
1971	15130
1972	15800
1973	16670
1974	17380
1975	17300
1976	18180
1977	19650
1978	20650
1979	21450
1980	22430
1981	23120
1982	23270
1983	22500
1984	23220
1985	23820
1986	25110
1987	26920
1988	26440
1989	26320
1990	26370
1991	26330
1992	25140
1993	25030
1994	25940
1995	25840
1996	27030
1997	28060
1998	29260
1999	30040
2000	31090
2001	31830
2002	31160
2003	31940
2004	34280
2005	35630
2006	36360
2007	37840
2008	37920
2009	35090
2010	33320
2011	33930
2012	34370
2013	34830
2014	35380
2015	35930
2016	36340
2017	36850
2018	37520