Year	Measure
1800	861.8
1820	861.8
1870	955.9
1900	2181
1901	2402
1902	2271
1903	1954
1904	1888
1905	2090
1906	2349
1907	2142
1908	2460
1909	2488
1910	2702
1911	2421
1912	2071
1913	1792
1914	2142
1915	2184
1916	1806
1917	2502
1918	1956
1919	2219
1920	1911
1921	2159
1922	2852
1923	2920
1924	2857
1925	3219
1926	2657
1927	1965
1928	2335
1929	3287
1930	3016
1931	2222
1932	1934
1933	2735
1934	3227
1935	3635
1936	3612
1937	3923
1938	3326
1939	3869
1950	3533
1951	3331
1952	2315
1953	2763
1954	3166
1955	2913
1956	3204
1957	2843
1958	2849
1959	3203
1960	3426
1961	3783
1962	3675
1963	3908
1964	3827
1965	4181
1966	4527
1967	4977
1968	5567
1969	6236
1970	6994
1971	7705
1972	8598
1973	9392
1974	9803
1975	9966
1976	10540
1977	11210
1978	12030
1979	13000
1980	14100
1981	14780
1982	15170
1983	16270
1984	17310
1985	17040
1986	17420
1987	18860
1988	20540
1989	21990
1990	23140
1991	23980
1992	24770
1993	27040
1994	29300
1995	30790
1996	31930
1997	33520
1998	31920
1999	33980
2000	36830
2001	34910
2002	36020
2003	37020
2004	39800
2005	41480
2006	43220
2007	44670
2008	44100
2009	42990
2010	48320
2011	49590
2012	49380
2013	49510
2014	51160
2015	52400
2016	53590
2017	54770
2018	55950