Year	Number of
1990	82.35
1991	84.09
1992	86.52
1993	89.23
1994	91.82
1995	94.64
1996	98.08
1997	101.52
1998	105.06
1999	117.61
2000	132.46
2001	148.44
2002	166.81
2003	187.26
2004	208.78
2005	232.76
2006	246.54
2007	253.28
2008	265.24
2009	278.68
2010	296.58
2011	311.24
2012	329.08
2013	350.06
2014	368.5
2015	382.64
2016	399.02