Year	Number of
1990	51.26
1991	53.65
1992	53.41
1993	54.11
1994	55.1
1995	56.7
1996	57.94
1997	60.1
1998	57.54
1999	57.59
2000	60.39
2001	62.75
2002	63.01
2003	66.24
2004	67.82
2005	71.22
2006	72.97
2007	74.36
2008	77.17
2009	80.61
2010	84.11
2011	84.68
2012	86.48
2013	87
2014	91.79
2015	91.77
2016	92.5