Year	Number
1976	3.527025764080637
1977	4.467822739407985
1978	3.5559381542310042
1979	4.792742469733656
1980	5.97364195034185
1981	3.3758495476001706
1982	5.93845725024074
1983	5.3405029889845395
1984	5.7596160279044675
1985	5.376052715540184
1986	5.27193338451115
1987	5.257598778030506
1988	5.024334911836697
1989	5.157675284962234
1990	4.529531663473635
1991	3.6541552399375026
1992	3.6720680137599384
1993	4.16697453962911
1994	6.126553592836649
1995	6.6706071257931
1996	7.936071440042087
1997	6.9191084586094584
1998	5.875709252729153
1999	6.397506915098891
2000	5.816703290142326
2001	5.948297777768309
2002	4.501316077876469
2003	5.435328769874444
2004	5.465434673056922
2005	6.406499092878404
2006	9.37204798379078
2007	12.75404833367712
2008	13.907560725071848
2009	16.973118881658454
2010	16.38577102934629
2011	14.539543262343573
2012	14.294010122545597
2013	13.178061839472706
2014	12.337398620235753
2015	11.912608514248268
2016	10.447299733372564
2017	9.419597673324969
2018	7.909140498035686
2019	5.9882723478185484
2020	7.325881434901174
2021	5.02740490789086
2022	3.037841483700577
2023	1.4888948578436523