Year	Number
1996	3.11
1997	5
1998	1.93
1999	0.17
2000	2
2001	0.64
2002	1.28
2003	1.33
2004	1.88
2005	3.71
2006	2.71
2007	3.28
2008	2.82
2009	8.12
2010	6.87
2011	4.24
2012	7.42
2013	6.45
2014	7.01
2015	5.71
2016	4.19
2017	5.24
2018	6.16
2019	5.68
2020	8.84