Year	Measure
1800	829.6
1820	829.6
1913	1122
1973	2282
1974	2973
1975	2747
1976	2714
1977	2606
1978	2973
1979	3000
1980	2585
1981	2624
1982	2835
1983	3359
1984	3508
1985	3464
1986	3315
1987	3251
1988	3191
1989	3218
1990	3282
1991	3575
1992	3443
1993	3492
1994	3482
1995	3556
1996	3730
1997	3840
1998	3936
1999	3741
2000	3762
2001	3575
2002	3234
2003	3251
2004	3341
2005	3477
2006	3687
2007	3791
2008	3945
2009	3985
2010	3959
2011	3926
2012	3941
2013	4017
2014	4096
2015	4165
2016	4235
2017	4306
2018	4378