Year Number of 1990 5028.74 1991 5419.14 1992 5859.41 1993 6348.25 1994 6923.79 1995 7616.88 1996 8152.29 1997 8705.02 1998 9288.22 1999 9881.29 2000 10450.87 2001 10910.52 2002 11366.6 2003 11795.33 2004 12280.71 2005 12806.21 2006 13171.81 2007 13585.1 2008 14091.72 2009 14656.96 2010 15271.54 2011 15904.71 2012 16612.23 2013 17378.61 2014 18316.49 2015 19339.12 2016 20535.65