Year	Number
1965	11.110211663711604
1966	8.711346604978397
1967	9.97686835174666
1968	5.162206732287984
1969	7.045387006368631
1970	10.247259716073026
1971	15.085748380711296
1972	7.2436698434030635
1973	6.763298219072819
1974	5.500119367762502
1975	7.662185189415309
1976	9.90349120573179
1977	11.50909347096916
1978	10.228528909890379
1979	5.84287557553043
1980	5.4795296215921745
1981	10.31435870060418
1982	10.45797023003572
1983	12.058409495065902
1984	16.48747528661501
1985	16.556257529539415
1986	14.786335458419936
1987	12.91094000618404
1988	23.078755878448998
1989	24.217828727393496
1990	23.332754268081267
1991	20.753892519263307
1992	20.53235759283725
1993	21.22459808033582
1994	20.194860029843362
1995	16.93329746077926
1996	31.127177419417748
1997	13.445631675248233
1998	13.77630518272415
1999	10.15798671105723
2000	9.332140863764408
2001	9.130559784101795
2002	8.60675299936634
2003	13.031450121657988
2004	9.45870719162382
2005	8.370146320690484
2006	7.767539911539052
2007	7.19322804071648
2008	6.800896301999756
2009	5.804611553547861
2010	6.492823367413213
2011	6.375519277058084
2012	5.703406684864128
2013	5.240562395821637
2014	5.062685706122267
2015	5.085141112517749
2016	4.548018559706975
2017	4.974251683203143
2018	5.190087222776032
2019	4.731509304297514
2020	4.548978836860123
2021	5.114807641048912
2022	4.775698226282306
2023	4.41376574494209