Year	Number of
1990	47.88
1991	49.27
1992	49.74
1993	50.33
1994	50.28
1995	49.21
1996	49.28
1997	49.66
1998	51.43
1999	55.3
2000	55.74
2001	57.13
2002	58.4
2003	59.91
2004	63.45
2005	66.59
2006	67.89
2007	71.59
2008	75.23
2009	78.35
2010	81.32
2011	83.45
2012	85.24
2013	84.39
2014	83.94
2015	83.53
2016	84.01