Year	Number of
1990	79.32
1991	81.92
1992	84.56
1993	87.12
1994	89.65
1995	92.14
1996	95.6
1997	98.81
1998	102.36
1999	105.69
2000	108.96
2001	113.18
2002	117.52
2003	122.1
2004	126.93
2005	132.25
2006	135.92
2007	139.24
2008	140.83
2009	142.07
2010	143.19
2011	145.49
2012	148.2
2013	149.52
2014	150.81
2015	152.01
2016	156.16