Year	Number of
1990	74.78
1991	77.79
1992	81.03
1993	84.84
1994	89.31
1995	94.67
1996	99.85
1997	105.55
1998	115.75
1999	126.12
2000	134.91
2001	141.56
2002	147.99
2003	159.58
2004	169.44
2005	178.61
2006	186.74
2007	194.46
2008	205.98
2009	218.8
2010	235.01
2011	251.94
2012	267.41
2013	287.61
2014	309.79
2015	326.63
2016	344.99