Year	Number of
1990	233.77
1991	233.72
1992	237.89
1993	241.15
1994	248.07
1995	247.87
1996	245.6
1997	247.01
1998	247.55
1999	255.55
2000	260.97
2001	269.64
2002	277.55
2003	286.14
2004	296.54
2005	305.85
2006	319.8
2007	332.16
2008	345.16
2009	357.87
2010	371.92
2011	386.44
2012	403.21
2013	423.04
2014	442.98
2015	466.2
2016	490.91