Year	Number
1961	13.784461152882205
1962	15.037593984962406
1963	17.543859649122805
1964	22.55639097744361
1965	30
1966	33.75
1967	36.25
1968	37.5
1969	38.6
1970	40
1971	41.25
1972	42.394014962593516
1973	43.64089775561097
1974	44.88778054862843
1975	46.13466334164589
1976	47.381546134663346
1977	48.6284289276808
1978	49.87531172069826
1979	50.86848635235732
1980	53.349875930521094
1981	56.82382133995038
1982	60.74074074074074
1983	63.456790123456784
1984	66.91358024691358
1985	70.51597051597052
1986	73.95577395577395
1987	77.01711491442543
1988	113.6919315403423
1989	120.77294685990339
1990	140.47619047619045
1991	133.66666666666666
1992	154.68
1993	110.00000000000001
1994	96.20253164556962
1995	108.69565217391303
1996	107.24637681159422
1997	122.30000000000001
1998	145.95652173913044
1999	152
2000	76.8
2001	158.25
2002	127.87755102040816
2003	151.64102564102564
2004	135.75221238938053
2005	121.37500000000001
2006	140.0995024875622
2007	155.76923076923077
2008	120.82437275985663