Year	Number
1974	5.2784145683584764
1975	2.788315142778379
1976	2.547680513867245
1977	1.8568817698312992
1978	2.8099079658204045
1979	3.1586648007957647
1980	3.05374746058266
1981	2.2339796136117007
1982	2.6553630042927194
1983	2.49931630164229
1984	1.8223075120422916
1985	1.6550338685230186
1986	2.1631065685316395
1987	2.23734438499521
1988	2.113513842410825
1989	3.1294539015295615
1990	2.9346664881457887
1991	2.727417194139803
1992	2.930855217238333
1994	2.7398567709063513
1995	3.3887371590241466
1996	3.4610771543048995
1997	3.6952414933342794
1998	4.316018012326367
1999	4.789018102529087
2000	4.559745272560127
2001	4.766603921651894
2002	5.443667832036824
2003	5.951158497750689
2004	7.02820714507214
2005	7.914371266320627
2006	9.91876071137819
2007	11.703458713436909
2008	7.941520890972929
2009	11.98364606652639
2010	10.486597663814575
2011	8.65330776197673
2012	8.82014778874884
2013	8.213831011576831
2014	7.080620447699327
2015	9.18044038319204
2016	9.693395778022714
2017	9.213999735705825
2018	9.135259642518138
2019	10.30301994854113
2020	13.10197705452896
2021	10.65622141539848
2022	10.455508896231132
2023	10.493704706997267