Year	Number of
1990	134.45
1991	140.69
1992	147.31
1993	154.32
1994	161.77
1995	169.76
1996	178.21
1997	187.27
1998	196.99
1999	207.13
2000	217.78
2001	228.04
2002	238.99
2003	250.83
2004	263.37
2005	276.87
2006	289.23
2007	302.06
2008	315.88
2009	330.44
2010	346.02
2011	362.09
2012	379.41
2013	397.77
2014	417.15
2015	437.53
2016	459.1