Year	Number
1960	7.407534432721719
1961	14.587708931713815
1962	7.36761092433877
1963	6.567641547975364
1964	5.922153217361103
1965	5.9502762249237815
1966	7.117946058276008
1967	8.941827729129907
1968	7.703537608514814
1969	6.189544481064087
1970	11.769705655444888
1971	9.180377954315777
1972	7.339248595262532
1973	7.201356173885112
1974	8.162893914432313
1975	10.010406117549547
1976	7.434945171414282
1977	4.990804633160501
1978	6.100025120830871
1979	10.693394347884581
1980	10.295711166789397
1981	10.448024828432436
1982	4.429014128675826
1983	4.018214874585319
1984	3.6523426220146282
1985	2.8885741200902366
1986	3.0173137369194145
1987	3.3069305913747122
1988	2.93802929410432
1989	2.904979608697216
1990	4.659778215059985
1991	2.6257316532784087
1992	2.6774605455313356
1993	2.900074329008901
1994	3.666496930129974
1995	2.8699806762654796
1996	3.878319242999203
1997	1.4973410873893327
1998	1.9331135691827979
1999	1.649477335423044
2000	2.101750440099474
2001	4.965002677230646
2002	4.793247446443495
2003	4.40413308910437
2004	4.711522891859946
2005	4.580866576027216
2006	3.9015704362494397
2007	3.5227753600465537
2008	4.5875507840382
2009	4.299624159328076
2010	4.158079004646161
2011	4.435583823966615
2012	3.4007075810183442
2013	3.5085691563500716
2014	3.7837349504337254
2015	3.6488265525262844
2016	3.8179583017098437
2017	3.942137162439466
2018	3.775817690295438
2019	3.2391156970101784
2020	4.733967644888838
2021	5.068997097550684
2022	3.8417277547357007
2023	3.1100797127943784