Year Number of 1990 5917.39 1991 6185.83 1992 6493.51 1993 6863.74 1994 7281.51 1995 7734.52 1996 8139.9 1997 8823.64 1998 9404.13 1999 10032.78 2000 10733.29 2001 10904.24 2002 11153.26 2003 11359.3 2004 11570.06 2005 11786.89 2006 11888.49 2007 11987.89 2008 12103.83 2009 12263.85 2010 12442.17 2011 12692.1 2012 12997.25 2013 13361.13 2014 13742.97 2015 14188.23 2016 14617.11