Year	Number of
1990	194.33
1991	192.54
1992	188.89
1993	186.27
1994	184.54
1995	180.88
1996	179.74
1997	179.17
1998	179.7
1999	183.49
2000	186.58
2001	190.2
2002	196.55
2003	201.86
2004	206.41
2005	209.93
2006	218.1
2007	227.09
2008	238.82
2009	249.61
2010	260.86
2011	270.17
2012	280.85
2013	290.25
2014	300.6
2015	311.3
2016	317.81