Year Number of 1990 15088.94 1991 15632.42 1992 15494.01 1993 15227.17 1994 15368.27 1995 15897.53 1996 15653.73 1997 15882.79 1998 16031.04 1999 16796.68 2000 16527.69 2001 16509.49 2002 16517.72 2003 16565.93 2004 16818.08 2005 16871.95 2006 16957.98 2007 17079.69 2008 17026.84 2009 16956.21 2010 16885.45 2011 16789.6 2012 17016.04 2013 16886.26 2014 16389.83 2015 16244.49 2016 16153.4