Year	Number
1978	2.662417798854667
1979	0.16030557371897305
1980	0.35987360141359814
1981	0.31077099006853315
1982	0.7446742770496759
1983	0.2711065617287167
1984	0.2641768194391218
1985	0.20945605287913516
1986	2.1136520764841804
1987	1.9081763189563945
1988	1.3578166124658646
1989	1.389110431601107
1990	3.1358820889575627
1991	3.32310912030565
1992	4.36001279113918
1993	4.444779407991989
1994	4.677437908919214
1995	5.31392179885268
1996	4.09259679742722
1997	4.03679678576567
2003	3.798664742778679
2004	3.636651890537566
2005	3.8674542909440457
2006	4.0353472049346975
2007	4.121801113548099
2008	3.510828955528956
2009	7.429276026711411
2010	7.110878177237417
2011	6.403204110519976
2012	6.414045447252883
2013	6.343441191523904
2014	3.991872417431716
2015	3.111068235690094
2016	2.6106653719916264
2017	3.436033907523483
2018	3.1854191840072117
2019	4.614154937679965
2020	6.406760813654086
2021	10.017658499050265
2022	7.800570635175744