Year	Measure
1800	627
1820	627
1870	669.7
1902	722.1
1903	862.6
1904	728.9
1905	760.9
1906	775.5
1907	801.9
1908	831.8
1909	831.4
1910	938.4
1911	979.6
1912	978.2
1913	1061
1914	1022
1915	939.4
1916	1077
1917	1232
1918	1380
1919	1301
1920	1384
1921	1326
1922	1457
1923	1342
1924	1437
1925	1421
1926	1464
1927	1466
1928	1494
1929	1516
1930	1483
1931	1460
1932	1489
1933	1469
1934	1447
1935	1317
1936	1464
1937	1532
1938	1546
1939	1619
1940	1618
1946	693.5
1947	939.3
1948	1066
1949	1100
1950	1149
1951	1235
1952	1273
1953	1346
1954	1404
1955	1457
1956	1513
1957	1548
1958	1554
1959	1611
1960	1585
1961	1623
1962	1650
1963	1712
1964	1718
1965	1753
1966	1775
1967	1814
1968	1848
1969	1878
1970	1894
1971	1940
1972	1989
1973	2108
1974	2124
1975	2183
1976	2310
1977	2373
1978	2428
1979	2494
1980	2550
1981	2574
1982	2603
1983	2593
1984	2348
1985	2126
1986	2148
1987	2190
1988	2285
1989	2372
1990	2387
1991	2320
1992	2279
1993	2279
1994	2329
1995	2384
1996	2465
1997	2537
1998	2470
1999	2503
2000	2599
2001	2591
2002	2651
2003	2727
2004	2847
2005	2932
2006	3025
2007	3162
2008	3228
2009	3247
2010	3435
2011	3508
2012	3677
2013	3831
2014	3962
2015	4090
2016	4226
2017	4371
2018	4521