Year	Number
1996	15.86
1997	19.79
1998	13.59
1999	8.78
2000	14.14
2001	10.86
2002	7.63
2003	13.66
2004	17.2
2005	21.36
2006	33.28
2007	22.34
2008	27.14
2009	27.96
2010	30.29
2011	30.27
2012	31.51
2013	28.3
2014	32.81
2015	25.92
2016	37.54
2017	40.21
2018	33.4
2019	34.48
2020	37.67