Year	Number of
1990	57.66
1991	60.29
1992	64.82
1993	68.63
1994	75.56
1995	80.72
1996	85.68
1997	92.27
1998	101.01
1999	107.95
2000	113.57
2001	117.03
2002	121.79
2003	128.94
2004	137.09
2005	142.94
2006	148.64
2007	154.62
2008	161.58
2009	167.07
2010	173.83
2011	180.82
2012	186.2
2013	190.88
2014	198.15
2015	206.74
2016	215.46