Year	Number
1960	24.32410808180566
1961	12.384886939557438
1962	15.337751916269168
1963	12.148044877065756
1964	9.044537282148156
1965	5.624177769783959
1966	5.40266947374804
1967	6.692694023565069
1968	6.558372502477071
1969	9.109208628277814
1970	6.08957219930392
1971	5.722692256037497
1972	4.740934437884207
1973	3.368000613747227
1974	2.6626912999119163
1975	2.551853847532722
1976	2.3005854141222963
1977	1.775567054540417
1978	1.3808709926867637
1979	1.2338771622259326
1980	1.3308996476016701
1981	1.5179102202051127
1982	1.6132398423429286
1983	1.9098003282907985
1984	1.3690697514854238
1985	1.135967911063446
1986	1.4590648508461321
1987	1.366500529560849
1988	2.101253348213352
1989	2.009316203091526
1990	1.7574147447031816
1991	1.6914654566204297
1992	3.4832101027409563
1993	3.4068218726038717
1994	2.3935849142341317
1995	2.2033473456848682
1996	2.405317230245489
1997	3.0014677526709357
1998	2.4947325313577013
1999	2.178595308763675
2000	2.5643950013854964
2001	3.2459843471525796
2002	2.6682015092296485
2003	1.7169111372157841
2004	1.7890497783647585
2005	1.7305360506064646
2006	1.6004785685606686
2007	1.6102358720039476
2008	2.1490367120186304
2009	1.7003000097553014
2010	1.9592112431931747
2011	2.148963631616759
2012	2.2692637297362803
2013	2.3904444871517416
2014	2.237503344338023
2016	2.1725577289964857
2017	2.0759884362674246
2018	2.250324338525016
2019	2.2636886650464985
2020	2.086016148581937
2021	2.1510557411955404
2022	2.2053316743799454
2023	2.2114226921595486