Year	Measure
1800	596
1801	596
1802	596
1803	596
1804	596
1805	596
1806	596
1807	596
1808	596
1809	596
1810	596
1811	596
1812	596
1813	596
1814	596
1815	596
1816	596
1817	596
1818	596
1819	596
1820	596
1821	596.1
1822	596.2
1823	596.2
1824	596.3
1825	596.4
1826	596.5
1827	596.6
1828	596.6
1829	596.7
1830	596.8
1831	596.9
1832	597
1833	597
1834	597.1
1835	597.2
1836	597.3
1837	597.4
1838	597.4
1839	597.5
1840	597.6
1841	597.7
1842	597.8
1843	597.8
1844	597.9
1845	598
1846	598.1
1847	598.2
1848	598.2
1849	598.3
1850	598.4
1851	598.5
1852	598.6
1853	598.6
1854	598.7
1855	598.8
1856	598.9
1857	599
1858	599
1859	599.1
1860	599.2
1861	599.3
1862	599.4
1863	599.4
1864	599.5
1865	599.6
1866	599.7
1867	599.8
1868	599.8
1869	599.9
1870	600
1871	602.3
1872	604.6
1873	606.9
1874	609.2
1875	611.5
1876	613.9
1877	616.2
1878	618.6
1879	620.9
1880	623.3
1881	625.7
1882	628.1
1883	630.5
1884	632.9
1885	635.3
1886	637.7
1887	640.1
1888	642.6
1889	645
1890	647.5
1891	650
1892	652.4
1893	654.9
1894	657.4
1895	659.9
1896	662.5
1897	665
1898	667.5
1899	670.1
1900	672.6
1901	675.2
1902	677.8
1903	680.4
1904	682.9
1905	685.6
1906	688.2
1907	690.8
1908	693.4
1909	696.1
1910	698.7
1911	701.4
1912	723.2
1913	742.9
1914	768.1
1915	889.2
1916	860.9
1917	942.4
1918	1005
1919	1058
1920	910.5
1921	971
1922	881.6
1923	933.1
1924	928
1925	917.2
1926	940.3
1927	969.4
1928	964.8
1929	902.9
1930	844.7
1931	839.3
1932	830.8
1933	993.4
1934	981.1
1935	1058
1936	1144
1937	1251
1938	1305
1939	1168
1940	1307
1941	1314
1942	1295
1943	1303
1944	1236
1945	575.7
1946	582.4
1947	613.8
1948	660
1949	708.1
1950	743.1
1951	689.3
1952	736.2
1953	950.5
1954	1003
1955	1050
1956	1039
1957	1097
1958	1130
1959	1145
1960	1137
1961	1163
1962	1169
1963	1243
1964	1322
1965	1375
1966	1512
1967	1594
1968	1768
1969	2003
1970	2141
1971	2319
1972	2458
1973	2844
1974	3056
1975	3225
1976	3568
1977	3899
1978	4224
1979	4492
1980	4331
1981	4558
1982	4859
1983	5373
1984	5804
1985	6162
1986	6849
1987	7612
1988	8441
1989	8948
1990	9764
1991	10620
1992	11150
1993	11700
1994	12610
1995	13670
1996	14570
1997	15200
1998	14360
1999	15690
2000	17000
2001	17780
2002	18870
2003	19490
2004	20440
2005	21340
2006	22340
2007	23370
2008	23740
2009	23700
2010	25080
2011	25800
2012	26200
2013	26820
2014	27740
2015	28720
2016	29730
2017	30770
2018	31840