Year Number of 1990 6375.94 1991 6573.8 1992 6800.41 1993 7010.89 1994 7246.48 1995 7482.86 1996 7805.8 1997 8163.46 1998 8498.12 1999 8865.8 2000 9278.53 2001 9737.69 2002 10217.25 2003 10746.79 2004 11320.96 2005 12007.17 2006 12345.93 2007 12816.39 2008 13283.1 2009 13917.28 2010 14592.61 2011 15290.96 2012 15976.5 2013 16806.36 2014 17654.89 2015 18449.72 2016 19190.57