Year	Number of
1990	134.73
1991	137.77
1992	139.64
1993	140.94
1994	142.38
1995	144.61
1996	150.45
1997	157.62
1998	165.62
1999	174.24
2000	183.38
2001	192.17
2002	201.64
2003	211.64
2004	222.28
2005	233.77
2006	238.87
2007	244.04
2008	249.85
2009	256.07
2010	262.95
2011	271.08
2012	280.25
2013	290.18
2014	300.7
2015	311.75
2016	323.85