Year Number of 1990 2798.6 1991 2962.84 1992 3163.84 1993 3359.19 1994 3597.98 1995 3862.52 1996 4110.46 1997 4327.71 1998 4566.64 1999 4751.66 2000 4907.96 2001 5039.71 2002 5123.11 2003 5243.48 2004 5432.63 2005 5610.78 2006 5636.9 2007 5713.96 2008 5761.53 2009 5814.96 2010 5929.13 2011 6047.17 2012 6122.8 2013 6202.92 2014 6322.08 2015 6429.05 2016 6518.63