Year	Number of
1990	94.78
1991	95.77
1992	89.8
1993	86.51
1994	95.01
1995	106.31
1996	133.18
1997	139.86
1998	150.35
1999	157.77
2000	166.46
2001	176.08
2002	188.4
2003	194.5
2004	211.64
2005	228.83
2006	241.44
2007	252.27
2008	264.33
2009	271.27
2010	281.24
2011	278.59
2012	292.24
2013	301.42
2014	308.55
2015	315.91
2016	320.17