Year	Number of
1990	44.53
1991	45.04
1992	45.31
1993	48.74
1994	54.58
1995	56.28
1996	55.83
1997	54.74
1998	57.5
1999	56.27
2000	53.03
2001	56.11
2002	55.95
2003	58.4
2004	61.79
2005	67.86
2006	69.12
2007	70.42
2008	72.64
2009	68.25
2010	70.05
2011	71.39
2012	71.85
2013	71.16
2014	70
2015	72.46
2016	72.62