Year	Number of
1990	135.32
1991	140.06
1992	145.37
1993	150.4
1994	155.45
1995	160.91
1996	165.71
1997	170.22
1998	173.61
1999	175.5
2000	173.79
2001	174.52
2002	174.54
2003	184.59
2004	190.58
2005	197.5
2006	198.56
2007	200.63
2008	202.13
2009	202.45
2010	206.71
2011	210.28
2012	216.09
2013	223.27
2014	230.99
2015	237.92
2016	244.06