Year	Number of
1990	245.66
1991	256.82
1992	270.35
1993	284.89
1994	298.87
1995	311.62
1996	318.87
1997	324.31
1998	328.4
1999	332.45
2000	337.35
2001	339.65
2002	342.73
2003	346.4
2004	350.75
2005	355.99
2006	362.67
2007	370.27
2008	379.25
2009	389.11
2010	400.04
2011	409.54
2012	420.13
2013	431.34
2014	443.38
2015	456.32
2016	469.63