Year	Number of
1990	88.28
1991	85.87
1992	84.89
1993	82.92
1994	82.09
1995	79.96
1996	75.94
1997	74.49
1998	72.95
1999	72.25
2000	71.45
2001	71.28
2002	70.72
2003	69.95
2004	68.81
2005	67.36
2006	69.24
2007	71.4
2008	73.67
2009	74.07
2010	74.43
2011	74.95
2012	75.66
2013	76.49
2014	78.46
2015	80.83
2016	83.42