Year	Number
1977	3.6850477584113737
1978	1.6130729506090316
1979	4.434421596320588
1980	5.802159730398921
1981	1.9705755742706632
1982	1.1713597379366305
1983	1.0149602582136583
1984	1.6892333403334365
1985	2.1322860098690364
1986	3.2121644406215943
1987	2.281205758413572
1988	1.480136435627847
1989	3.2175234298844355
1990	5.025940643450185
1991	4.354123229068249
1992	1.249728317178791
1993	1.5472172910634374
1994	1.582647158897477
1995	4.1662245850559065
1996	11.512495075992494
1997	17.376181844938106
1998	19.209601786639006
1999	4.555772385556156
2000	7.878411725672103
2001	6.820118386851305
2002	4.868416509093884
2003	3.532254719790612
2004	8.747991003765904
2005	9.604675415492247
2006	12.098219903406743
2007	10.218037150524589
2008	7.8814477389410875
2009	7.984110551657946
2010	4.377885256675866
2011	3.5318419473495566
2012	5.19347277530649
2013	5.085620337794163
2014	3.9242129422713616
2015	4.067692567563323
2016	6.169071282256131
2017	7.997765172858989
2018	6.052105543789252
2019	4.096430134021238
2020	5.604195242717902
2021	6.230226893632784
2022	4.659506677352003