Year	Measure
1800	620.5
1820	620.5
1913	1145
1970	5849
1971	5985
1972	6076
1973	6207
1974	6429
1975	6722
1976	6607
1977	6492
1978	6872
1979	7670
1980	8470
1981	8775
1982	9223
1983	9067
1984	9337
1985	10020
1986	10440
1987	11010
1988	12250
1989	13320
1990	15310
1991	12070
1992	12280
1993	12540
1994	12860
1995	12440
1996	10710
1997	9816
1998	10510
1999	11450
2000	12740
2001	12700
2002	13380
2003	12180
2004	12130
2005	11580
2006	11380
2007	11720
2008	12040
2009	12050
2010	11510
2011	11600