Year	Number of
1990	67.96
1991	67.44
1992	69.01
1993	71.32
1994	74.35
1995	78.29
1996	83.08
1997	86.82
1998	90.89
1999	93.87
2000	95.77
2001	95.8
2002	95.47
2003	94.83
2004	93.43
2005	91.72
2006	89.69
2007	88.72
2008	88.65
2009	87.69
2010	87.16
2011	86.8
2012	88.13
2013	88.43
2014	88.09
2015	87.85
2016	87.63