Year	Number
1984	4.783303579420262
1985	4.995641744372839
1986	5.2830168435466485
1987	4.577302331890253
1988	4.848358663703066
1989	5.403290905184055
1990	3.534741613570762
1991	3.4438788247627348
1992	3.9108044646975
1993	4.38282317432384
1994	4.6258607696525
1995	4.978261241465715
1996	4.321119983311881
1997	4.769126511902155
1998	4.580950966089304
1999	4.14570964614308
2000	4.365701776066821
2001	4.5272106911277925
2002	4.995803193498055
2003	4.330488680833128
2004	5.256571196040931
2005	6.159751683266843
2006	5.100145682080505
2007	5.026342043951585
2008	4.5814244889404705
2009	3.890219188889017
2010	4.239215735302148
2011	4.130910301507427
2012	4.666015557443498
2013	2.9192756830981788
2014	3.3602186927726785
2015	4.309623505582213
2016	4.19777099115772
2017	3.7495110795912514
2018	4.3344899402467085
2019	4.267270766890156
2020	3.7249542374636646
2021	4.5749285489828635
2022	4.489873930230852
2023	5.676196969832455