Year	Number
1960	2.751599395950568
1961	3.222215455621496
1962	3.9589238788596637
1963	6.677146382806926
1964	14.075215070195748
1965	8.080492864850772
1966	9.129990464857844
1967	11.434016748733569
1968	10.946900276603527
1969	9.481697711655718
1970	8.237161151034266
1971	7.46833776193237
1972	6.78315109879537
1973	7.26792174100671
1974	5.3931096942262355
1975	8.048162395061729
1976	6.948291510723387
1977	7.351553467642363
1978	7.380838568463141
1979	7.556612100660443
1980	9.354118276969066
1981	13.238226776974054
1982	11.93239103121742
1983	17.090866769724165
1984	21.471866579427818
1985	16.369988035549344
1986	15.010891775301916
1987	11.628121633694619
1988	12.265548997001806
1989	14.444167308741301
1990	5.958554635016542
1991	4.598635902001965
1992	4.49358806885816
1993	4.327468333320865
1994	4.096755573724368
1995	5.638371700325323
1996	5.625607559521174
1997	5.776123145691668
1998	5.498331185744671
1999	4.672216993006525
2000	5.492108079516358
2001	3.5291556294265947
2002	3.336305018007723
2003	3.038161410621364
2004	3.020382750376419
2005	3.466178447733919
2006	3.2841057976255468
2007	3.4867579684480714
2008	4.5427516836031705
2009	4.50756773015795
2010	4.469018831485041
2011	5.818426702400047
2012	6.709508305651671
2013	6.473316402572161
2014	6.374061022445912
2015	5.168210327656654
2016	4.885258532460595
2017	4.999803821127359
2018	5.752006749498526
2019	5.395453507842211
2020	4.3441772086113275
2021	4.870951221906621
2022	5.132165107146116
2023	4.756239321045732