Year	Number
1992	19.898563939918283
1993	7.711816549347245
1994	6.131231495213981
1995	6.746636224243197
1996	8.04992306602635
1997	6.282137168105316
1998	5.5724987055051205
1999	5.133181192088989
2000	6.014345945850388
2001	5.709384062102076
2002	3.8998354417569647
2003	5.512320232197475
2004	7.453990859681111
2005	8.774687469812362
2006	7.444227149321717
2007	4.161218056681198
2008	2.793264277742673
2009	2.7209645585072355
2010	4.229016899050231
2011	4.501219742449773
2012	4.274077529335301
2013	4.680203496020353
2014	5.8261150290693795
2015	3.7309487652503637
2016	3.1903819763629837
2017	3.0307607505560465
2018	3.6676000876064694
2019	3.895616343385075
2020	3.4874904011881043
2021	3.258008784358443