Year	Number of
1990	106.74
1991	113.74
1992	123.21
1993	134.52
1994	146.11
1995	157.88
1996	164.52
1997	170.47
1998	175.83
1999	181.76
2000	189.45
2001	194.94
2002	202.3
2003	210.56
2004	219.14
2005	228.39
2006	235.6
2007	241.78
2008	248.72
2009	256.27
2010	265.58
2011	272.05
2012	280.4
2013	289.54
2014	299.15
2015	308.96
2016	320.63