Year	Number
1977	0.7945086019855458
1978	6.231810371995129
1979	5.289835854983623
1980	3.036047004449643
1981	2.205837233514646
1982	4.163623872864499
1983	5.368962392689117
1984	4.468813960865273
1985	3.455432539187726
1986	2.8039497113058665
1987	3.38476861259867
1988	2.5987028126781215
1989	1.7314944267130246
1990	1.290645496203974
1991	0.5377605250195853
1992	1.5988312588740905
1993	1.083998990897201
1994	0.8274574061392447
1995	0.7972298875078114
1996	1.5931176613240128
1997	1.4397506006460092
1998	2.621768431289111
1999	2.7906725163738133
2000	2.1801353384369824
2001	1.2494830300677027
2002	1.752457588733871
2003	2.727467877620486
2004	5.59988367179891
2005	4.548987369766485
2006	4.309331329041096
2007	3.565519169045644
2008	2.272043442839444
2009	4.240560966950349
2010	5.221845284915817
2011	6.940320690750052
2012	8.223402103760206
2013	8.43907973687581
2014	8.003847659791765
2015	8.957137664087377
2016	8.689957869133872
2017	9.184680776079732
2018	9.129229431195377
2019	8.373604570517466
2020	13.745499118965698
2021	12.700366803399724
2022	9.665777460339877