Year	Number of
1990	452.43
1991	470.28
1992	485.25
1993	495.87
1994	503.52
1995	518.93
1996	529.51
1997	539.48
1998	545
1999	549.78
2000	557.71
2001	561.54
2002	563.45
2003	554.51
2004	561.6
2005	558.83
2006	555.69
2007	556.14
2008	559.99
2009	573.43
2010	573.33
2011	587.54
2012	591.6
2013	602.1
2014	630.25
2015	656.95
2016	682.72