Year	Measure
1800	564.2
1820	564.2
1939	2456
1940	2272
1941	2257
1942	2333
1943	2328
1944	2324
1945	2192
1946	2353
1947	1999
1948	1976
1949	2256
1950	2054
1951	2039
1952	1952
1953	1956
1954	1938
1955	1975
1956	2006
1957	2046
1958	2107
1959	2049
1960	2016
1961	2059
1962	2148
1963	2151
1964	2187
1965	2254
1966	2220
1967	2299
1968	2319
1969	2346
1970	2427
1971	2465
1972	2523
1973	2642
1974	2780
1975	2878
1976	3001
1977	3248
1978	3526
1979	3830
1980	4283
1981	4535
1982	4259
1983	4015
1984	4024
1985	4065
1986	3944
1987	3999
1988	4137
1989	4254
1990	4261
1991	4245
1992	4196
1993	4243
1994	4249
1995	4318
1996	4255
1997	4247
1998	4117
1999	4029
2000	3907
2001	3885
2002	3784
2003	3828
2004	3886
2005	3900
2006	4007
2007	4142
2008	4319
2009	4066
2010	4508
2011	4612
2012	4467
2013	4861
2014	4985
2015	5117
2016	5253
2017	5392
2018	5534