Year	Number of
1990	303.64
1991	311.97
1992	322
1993	333.16
1994	344.17
1995	355.19
1996	365.29
1997	376.01
1998	386.97
1999	400.12
2000	415.82
2001	429.4
2002	444.32
2003	461.01
2004	478.78
2005	497.97
2006	508.6
2007	520.07
2008	532.97
2009	546.56
2010	561.25
2011	576.23
2012	590.8
2013	606.25
2014	622.87
2015	641.01
2016	660.12