Year	Number of
1990	77.4
1991	80.63
1992	84.36
1993	88.57
1994	92.54
1995	96.77
1996	99.59
1997	102.47
1998	105.72
1999	109.71
2000	112.82
2001	119.49
2002	125.82
2003	132.44
2004	139.85
2005	142.75
2006	147.76
2007	153.47
2008	159.92
2009	166.55
2010	173.45
2011	179.99
2012	186.84
2013	194.31
2014	202.3
2015	210.94
2016	219.38