Year	Number of
1990	205.91
1991	210.57
1992	216.27
1993	222.31
1994	228.89
1995	235.94
1996	241.13
1997	246.61
1998	252.84
1999	259.41
2000	266.48
2001	273.01
2002	280.18
2003	288.71
2004	297.77
2005	307.42
2006	317.62
2007	328.21
2008	340.04
2009	352.46
2010	365.65
2011	378.29
2012	391.7
2013	405.79
2014	420.98
2015	437.4
2016	454.99