Year	Number of
1990	267.36
1991	275.72
1992	290.4
1993	308.24
1994	317.86
1995	325.27
1996	323.78
1997	318.3
1998	318.13
1999	307.34
2000	309.87
2001	329.55
2002	338.12
2003	333.96
2004	345.75
2005	363.51
2006	379.27
2007	400.36
2008	423.78
2009	442.46
2010	465.26
2011	488.76
2012	504.69
2013	516.46
2014	522.1
2015	519.46
2016	524.44