Year	Number of
1990	241.63
1991	251.29
1992	261.85
1993	273.21
1994	285.24
1995	297.98
1996	311.04
1997	324.97
1998	339.87
1999	355.89
2000	373.19
2001	383.94
2002	395.63
2003	408.31
2004	421.98
2005	436.8
2006	452.49
2007	469.44
2008	488.12
2009	508.27
2010	530.11
2011	552.34
2012	576.22
2013	601.61
2014	628.89
2015	658.22
2016	687.69