Year	Number of
1990	231.74
1991	227.41
1992	222.67
1993	217.92
1994	212.89
1995	207.79
1996	215.66
1997	223.54
1998	231.11
1999	238.65
2000	246.12
2001	262.15
2002	278.54
2003	294.91
2004	311.78
2005	329.35
2006	327.71
2007	326.2
2008	325.28
2009	324.65
2010	324.34
2011	325.55
2012	327.52
2013	329.79
2014	332.57
2015	335.81
2016	340.6