Year	Number of
1990	174.94
1991	178.45
1992	183.81
1993	190.51
1994	198.6
1995	207.12
1996	209.61
1997	209.56
1998	211.05
1999	213.51
2000	218.81
2001	221.75
2002	226.15
2003	228.66
2004	232.8
2005	236.79
2006	240.75
2007	246.25
2008	251.52
2009	258.18
2010	264.39
2011	268.41
2012	272.05
2013	276.09
2014	281.28
2015	287.13
2016	296.94