Year	Number of
1990	99.17
1991	103.17
1992	106.93
1993	113.38
1994	119.84
1995	126.78
1996	134.3
1997	142.61
1998	151.66
1999	159.49
2000	158.57
2001	162.9
2002	167.48
2003	172.41
2004	177.16
2005	183.08
2006	190.16
2007	202.18
2008	215.77
2009	228.17
2010	234.34
2011	236.88
2012	239.33
2013	240.24
2014	242.41
2015	246.08
2016	252.2