Year	Number of
1990	56.19
1991	56.32
1992	58.27
1993	58.78
1994	62.14
1995	61
1996	62.03
1997	59.46
1998	57.55
1999	56.71
2000	54.89
2001	54.87
2002	56.46
2003	57.74
2004	58.44
2005	59.44
2006	61.05
2007	62.46
2008	65.65
2009	68.32
2010	73.05
2011	75.41
2012	81.09
2013	81.56
2014	82.68
2015	84.09
2016	85.82