Year	Number of
1990	182.09
1991	183.71
1992	186.12
1993	189.08
1994	192.44
1995	196.25
1996	199.24
1997	202.61
1998	206.16
1999	210.21
2000	215
2001	219.2
2002	224.07
2003	229.07
2004	234.32
2005	239.93
2006	243.36
2007	246.46
2008	250.17
2009	254.67
2010	260.41
2011	268.06
2012	277.32
2013	287.92
2014	299.24
2015	311.01
2016	323.05