Year	Number
1971	12.392573259092854
1972	16.169512871046965
1973	15.113316861417111
1974	13.513393936963551
1975	15.043402966077497
1976	16.437879185622116
1977	15.808613226004189
1978	17.78624499287207
1979	15.657977553104088
1980	12.615025135272829
1981	14.040982798286532
1982	15.791045678519492
1983	17.43329497096824
1984	15.65938490155402
1985	14.96906194238018
1986	14.339163783891074
1987	13.966044476266681
1988	11.060533144995171
1989	9.458851905658044
1990	7.580175326889438
1991	6.5048565478124285
1992	5.550930862685705
1993	6.212424846910763
1994	7.416370724390083
1995	5.234825161795214
1996	5.424287711484155
1997	5.244223938678046
1998	5.262665750087186
1999	4.625831491555591
2000	3.5295678898403025
2001	4.839892548124772
2002	6.151698909161874
2003	6.473739865109239
2004	4.185104226729657
2005	3.0512607467870216
2006	2.4911124218795697
2007	2.1027783143998335
2008	0.1576802927807274
2009	0.26813896085908856
2010	0.28421769151625226
2011	0.2102191340266158
2012	0.30035200120600114
2013	0.24472364800765536
2014	0.2505448427618377
2015	0.25138158805020827
2016	0.294383446170854
2017	0.3423786337554873
2018	0.40319786056342816
2019	0.34947842266425666
2020	0.33972513184886666
2021	0.3815956263868618
2022	0.3980696956193174