Year Number of 1990 4873.63 1991 5146.31 1992 5433.62 1993 5748.51 1994 6028.81 1995 6359.12 1996 6640.63 1997 6878.72 1998 7185.94 1999 7470.49 2000 7777.64 2001 8067.79 2002 8408.88 2003 8730.48 2004 9166.73 2005 9555.76 2006 9830.55 2007 9861.19 2008 10058.51 2009 10314.95 2010 10630.28 2011 10897.99 2012 11180.95 2013 11463.8 2014 11769.21 2015 12114.5 2016 12418.61