Year	Measure
1800	1375
1820	1421
1913	4207
1970	35730
1971	35590
1972	35540
1973	35540
1974	35560
1975	35600
1976	46300
1977	47760
1978	46250
1979	45770
1980	41480
1981	42810
1982	41500
1983	41110
1984	42250
1985	44580
1986	45730
1987	49300
1988	51400
1989	53010
1990	53500
1991	53750
1992	54970
1993	56600
1994	59710
1995	62410
1996	65890
1997	69780
1998	74300
1999	81090
2000	82750
2001	81250
2002	79590
2003	77250
2004	78810
2005	81830
2006	88390
2007	95880
2008	92610
2009	82380
2010	89000
2011	90040