Year	Measure
1800	407.4
1820	407.4
1913	629.4
1950	825.3
1951	840.9
1952	851.2
1953	865.9
1954	880.5
1955	893.6
1956	905.9
1957	918.2
1958	929
1959	944.1
1960	953.3
1961	971.4
1962	983.7
1963	999.7
1964	1019
1965	1034
1966	1119
1967	1215
1968	1319
1969	1424
1970	1533
1971	1769
1972	2264
1973	2658
1974	3077
1975	2897
1976	3271
1977	3215
1978	3640
1979	3818
1980	4178
1981	4399
1982	4551
1983	5080
1984	5450
1985	5656
1986	5890
1987	6206
1988	6960
1989	7620
1990	7829
1991	7965
1992	7954
1993	7861
1994	7898
1995	8030
1996	8282
1997	8647
1998	8991
1999	9417
2000	10110
2001	10540
2002	11000
2003	11390
2004	11720
2005	12060
2006	12570
2007	13010
2008	13240
2009	12460
2010	13180
2011	13690
2012	14050
2013	14460
2014	14880
2015	15350
2016	15830
2017	16380
2018	16860