Year	Measure
1800	661.9
1820	665
1950	771.3
1951	776.6
1952	781.7
1953	787.3
1954	792.1
1955	797.2
1956	801
1957	804.8
1958	808.4
1959	812
1960	815.9
1961	820.5
1962	825.6
1963	832.9
1964	837
1965	843.3
1966	852.7
1967	862.4
1968	870.3
1969	880.7
1970	1041
1971	1197
1972	1265
1973	1388
1974	1436
1975	1510
1976	1695
1977	1830
1978	1931
1979	1982
1980	1939
1981	2000
1982	1978
1983	2032
1984	2050
1985	1974
1986	1956
1987	1972
1988	1990
1989	1992
1990	1923
1991	1859
1992	1879
1993	1862
1994	1835
1995	1971
1996	2023
1997	2117
1998	2150
1999	2159
2000	2217
2001	2225
2002	2235
2003	2240
2004	2251
2005	2276
2006	2278
2007	2283
2008	2296
2009	2313
2010	2419
2011	2102
2012	2044
2013	2071
2014	2120
2015	2194
2016	2269
2017	2344
2018	2418