Year	Number of
1990	45.63
1991	46.95
1992	48.28
1993	49.77
1994	51.35
1995	53.14
1996	54.44
1997	55.92
1998	57.25
1999	58.64
2000	60.1
2001	61.67
2002	63.32
2003	65
2004	66.64
2005	68.34
2006	70.18
2007	72.18
2008	74.33
2009	76.56
2010	78.94
2011	81.56
2012	84.38
2013	87.28
2014	90.24
2015	93.3
2016	96.52