Year	Number
1996	8.37
1997	10.34
1998	13.89
1999	9.82
2000	6.13
2001	6.87
2002	3.72
2003	10.41
2004	10.4
2005	8.36
2006	13.25
2007	8.41
2008	10.14
2009	11.05
2010	14.24
2011	14.1
2012	10.58
2013	12.59
2014	17.22
2015	12.31
2016	27.42
2017	18.62
2018	21.88
2019	16.99
2020	17.32