Year	Number
1974	39.84211
1983	46.888
1985	44.83123
1986	45.51958
1987	45.68866
1988	45.78947
1989	46.26854
1990	45.67727
1991	35.23099
1992	38.17374
1993	38.36205
1994	40.34554
1995	37.17196
1997	38.25603
1998	37.33912
1999	36.31725
2000	35.2706
2001	34.02551
2002	32.36834
2003	33.11545
2004	31.96457
2005	33.43805
2006	25.6812
2007	27.32543
2008	26.90076
2010	35.38043
2011	27.41109