Year	Number
1970	34.08394
1971	33.38939
1972	33.66605
1973	34.2466
1976	33.87477
1977	34.79016
1978	32.22573
1979	33.85735
1980	35.82476
1981	35.27128
1982	37.22589
1983	36.99753
1984	38.16463
1985	39.98734
1986	42.28001
1987	44.105
1988	41.17956
1989	36.95616
1990	40.99619
1991	38.96169
1992	38.53585
1993	37.07169
1994	37.20261
1995	37.20776
1996	33.78198
1999	41.4422
2000	42.9015
2001	39.00579
2002	40.27665
2003	34.87788
2004	35.80647
2005	36.90999
2006	40.4173
2007	46.08983
2010	37.55319