Year	Number
1996	19.32
1997	37.3
1998	35.46
1999	27.63
2000	24.98
2001	25.78
2002	20.16
2003	23.92
2004	22.46
2005	21.18
2006	29.42
2007	29.41
2008	28.05
2009	53.24
2010	66.79
2011	31.39
2012	30.93
2013	31.32
2014	47.31
2015	52.53
2016	50.63
2017	57.09
2018	64.14
2019	63.16
2020	63.65