Year	Number of
1990	151.39
1991	149.16
1992	147.3
1993	152.58
1994	155.49
1995	162.17
1996	164.39
1997	168.82
1998	173.22
1999	171.73
2000	178.87
2001	176.68
2002	178.16
2003	178.11
2004	186.31
2005	197.29
2006	202.05
2007	209.08
2008	216.43
2009	231.48
2010	239.17
2011	251.02
2012	255.31
2013	265.22
2014	272.03
2015	282.76
2016	291.18