Year	Number of
1990	268.45
1991	267.91
1992	269.52
1993	274.42
1994	280.63
1995	285.28
1996	280.19
1997	277.48
1998	288.01
1999	286.33
2000	287.45
2001	292.13
2002	297.1
2003	309.14
2004	318.07
2005	325.84
2006	338.93
2007	350.78
2008	367.02
2009	382.16
2010	396.98
2011	415.61
2012	435.91
2013	458.05
2014	481.62
2015	507.16
2016	532.34