Year	Number
1961	51.368547418967594
1962	54.25400739827374
1963	55.94695399917116
1964	57.80346820809249
1965	56.15801704105344
1966	55.90756615728662
1967	57.164068299925766
1968	57.95310755489393
1969	62.245871559633024
1970	63.48623853211009
1971	64.22669104204753
1972	67.88990825688074
1973	73.58060962174072
1974	77.16660509789435
1975	79.89594946116685
1976	84.7457627118644
1977	89.90796318527411
1978	118.16283924843425
1979	148.38975694444446
1980	157.48031496062993
1981	167.48591244039878
1982	183.6720380144132
1983	199.5814089034503
1984	213.1624517637545
1985	224.97180043383946
1986	224.3313201035375
1987	228.5402097902098
1988	229.4372294372294
1989	239.54703832752614
1990	249.56217162872156
1991	260.25584472871634
1992	233.24462390260314
1993	298.5230374056831
1994	301.7843883245428
1995	316.2229321973731
1996	324.6681375117139
1997	309.47274480733523
1998	307.8443023746966
1999	287.2411489645958
2000	307.9435915744377
2001	322.27542817196786
2002	317.91553133514986
2003	325.1273227804542
2004	324.67116357504216
2005	382.5634022629731
2006	385.09404990403067
2007	400.09360374414973
2008	390.5677517032551