Year	Number of
1990	53.77
1991	56.41
1992	59.48
1993	63.63
1994	67.33
1995	72.12
1996	79.07
1997	86.87
1998	94.16
1999	102.35
2000	109
2001	117.85
2002	127.56
2003	137.64
2004	149.15
2005	158.25
2006	168.02
2007	179.42
2008	191.28
2009	204.11
2010	216.31
2011	227.95
2012	241.81
2013	255.27
2014	269.42
2015	279.46
2016	290.78