Year	Number of
1990	90.86
1991	97.12
1992	102.5
1993	108.12
1994	117.58
1995	121.5
1996	128.02
1997	134.73
1998	147.64
1999	157.87
2000	168.07
2001	176
2002	186.38
2003	196.38
2004	203.08
2005	210.78
2006	217.39
2007	223.15
2008	233.05
2009	245.86
2010	255.85
2011	266.84
2012	274.92
2013	282.99
2014	289.69
2015	298.42
2016	306.64