Year	Number
1961	67.12962962962963
1962	87.1559633027523
1963	86.36363636363636
1964	94.80812641083521
1965	94.15217391304348
1966	99.2421052631579
1967	109.03688524590164
1968	114.38
1969	115.37254901960785
1970	115.4510556621881
1971	126.41509433962264
1972	137.03703703703704
1973	149.34306569343065
1974	156.1938958707361
1975	170.8703374777975
1976	170.43478260869566
1977	172.41379310344826
1978	173.2418524871355
1979	173.2418524871355
1980	172.73504273504275
1981	173.46938775510205
1982	174.87266553480475
1983	176.9100169779287
1984	173.1748726655348
1985	168.93039049235995
1986	173.1748726655348
1987	180.16949152542372
1988	196.61016949152543
1989	207.90378006872854
1990	212.43523316062175
1991	163.8235294117647
1992	155.70934256055364
1993	156.82842287694973
1994	157.71230502599653
1995	154.90467937608318
1996	144.0727902946274
1997	136.85121107266437
1998	141.24783362218372
1999	142.11438474870016
2000	139.9134948096886
2001	132.30103806228374
2002	130.01730103806227
2003	102.37024221453288
2004	131.03806228373702
2005	150.96654275092936
2006	135.3082191780822
2007	126.5916955017301
2008	121.93442622950819