Year	Number of
1990	163.58
1991	173.76
1992	180.22
1993	185.77
1994	191.85
1995	197.61
1996	203.46
1997	209.34
1998	215.74
1999	221.74
2000	227.55
2001	232.65
2002	238.23
2003	244.81
2004	250.77
2005	256.29
2006	261.1
2007	265.55
2008	270.98
2009	277.2
2010	283.5
2011	289.42
2012	295.94
2013	302.31
2014	309.58
2015	317.18
2016	324.88