Year Number of 1990 5056.83 1991 5283.21 1992 5345.03 1993 5421.58 1994 5527.7 1995 5638.93 1996 5694.9 1997 5906.75 1998 5979.23 1999 6037.16 2000 6057.02 2001 6089.95 2002 6115.53 2003 6208.2 2004 6288.7 2005 6421.99 2006 6521.38 2007 6637.45 2008 6684.11 2009 6791.04 2010 6687.46 2011 6774.54 2012 6930.53 2013 6927.38 2014 6844.83 2015 6857.78 2016 6897.5