Year	Number
1974	0.9033924479714124
1975	2.7056229901447644
1976	4.130338241772525
1977	4.834828141532307
1978	3.994205284625619
1979	2.9256568035881614
1980	2.8898070642740823
1981	1.7725531857427792
1982	1.5573658806901989
1983	1.896680415801649
1984	1.9616054308483868
1985	2.7271026441520707
1986	2.784233269524342
1987	2.6971431851459795
1988	2.655862699654095
1989	2.894405097325542
1990	2.9842498749070567
1991	2.2418036103590224
1992	3.3665899864206232
1993	2.752704918047757
1994	2.991458453129522
1995	2.655654856482343
1996	2.2552418968300096
1997	2.6431843404666417
1998	2.9653833217372867
1999	3.49067866239529
2000	2.7746852787618086
2001	2.3985592660947535
2002	2.451644994874631
2003	1.6962726432301183
2004	1.8111964940108862
2005	1.2859043136529917
2006	1.8567429141448644
2007	3.493608985368725
2008	3.6334763730728112
2009	4.305605546077234
2010	2.9627280222152077
2011	2.950124911520266
2012	3.6559342215752464
2013	3.9184429280845623
2014	3.499884183678538
2015	3.140412436498837
2016	3.4007165812671993
2017	2.7845047431066385
2018	2.0923150735045923
2019	2.114432163537519
2020	2.985229087695346
2021	2.5779853275998965
2022	1.9288639712038875