Year Number of 1990 4515.49 1991 4728.46 1992 4945.51 1993 5227.26 1994 5453.61 1995 5693.61 1996 5924.02 1997 6144.36 1998 6439.28 1999 6710.75 2000 6881.72 2001 7115.83 2002 7355.3 2003 7597.53 2004 7781.17 2005 7975.04 2006 8122.61 2007 8343.97 2008 8500.52 2009 8665.06 2010 8809.44 2011 8977.7 2012 9173.25 2013 9137.81 2014 9139.15 2015 9185.87 2016 9285.21