Year	Measure
1800	750.1
1820	750.1
1870	824.4
1911	996.5
1912	1023
1913	1120
1914	1145
1915	1167
1916	1239
1917	1286
1918	1206
1919	1440
1920	1382
1921	1338
1922	1433
1923	1381
1924	1319
1925	1495
1926	1638
1927	1557
1928	1729
1929	2094
1930	2036
1931	1927
1932	1738
1933	1792
1934	1916
1935	1698
1936	1839
1937	1628
1938	1694
1939	2003
1940	1590
1941	1541
1942	2082
1947	1330
1948	1475
1949	1905
1950	1940
1951	1792
1952	1831
1953	1792
1954	1855
1955	1817
1956	1873
1957	1810
1958	1758
1959	1826
1960	1904
1961	1981
1962	2037
1963	2077
1964	2150
1965	2245
1966	2298
1967	2278
1968	2417
1969	2496
1970	2587
1971	2713
1972	2849
1973	3186
1974	3345
1975	3296
1976	3622
1977	3828
1978	4070
1979	4301
1980	4551
1981	4758
1982	4920
1983	5097
1984	5360
1985	5173
1986	5108
1987	5250
1988	5578
1989	5961
1990	6386
1991	6838
1992	7278
1993	7815
1994	8343
1995	8962
1996	9645
1997	10130
1998	9192
1999	9554
2000	10160
2001	9995
2002	10210
2003	10600
2004	11120
2005	11470
2006	11950
2007	12530
2008	12970
2009	12530
2010	13190
2011	13680
2012	14200
2013	14680
2014	15180
2015	15700
2016	16250
2017	16800
2018	17380