Year	Number
1966	5.036257527481722
1967	3.851244668126688
1968	3.242177613673682
1969	2.2672547809443686
1970	2.232452366355814
1971	3.0870911109952544
1972	2.976932186549069
1973	3.2827135356752315
1974	3.9506078955623467
1975	5.149114703732478
1976	3.5539319324454923
1977	2.803356433788179
1978	4.965247557004997
1979	3.203690144676704
1980	4.0366841670770786
1981	7.685757444314847
1982	7.885909433233575
1983	4.145117040687176
1984	4.234632393897556
1985	3.9281100809741187
1986	4.9490615965840545
1987	8.188445855510713
1988	8.145597522128384
1989	7.429345928275032
1990	10.73818403665267
1991	17.400555960346807
1992	37.68470322746303
1993	4.8813673849692245
1994	4.620382115426461
1995	9.942322373271752
1996	5.556474499052195
1997	6.213129907779338
1998	6.444869776703491
1999	5.827521895356928
2000	4.976023491278706
2001	4.297106670347313
2002	4.696978500032064
2003	3.9242608893197124
2004	4.165617926227765
2005	4.052219731146583
2006	3.69857678133907
2007	3.4349407368556317
2008	4.501682271173443
2009	3.5063160321457536
2010	3.731603184443969
2011	4.018597023472751
2012	3.6065058968065573
2013	3.53207250017491
2014	3.668304539920065
2015	3.995433722143536
2016	3.9941250261970485
2017	4.4069826301483666
2018	4.44503253789779
2019	4.192120393080747
2020	4.998454002431188
2021	4.50664703340371
2022	5.368092436467969
2023	5.887221247422736