Year Number of 1990 3059.43 1991 3132.16 1992 3278.46 1993 3408.58 1994 3573.64 1995 3730.18 1996 4000.83 1997 4262.89 1998 4521.24 1999 4821.26 2000 5102.67 2001 5382.88 2002 5648.82 2003 5930.85 2004 6194.28 2005 6655.54 2006 6857.61 2007 7187.81 2008 7435.26 2009 7681.46 2010 8014.8 2011 8323.65 2012 8602.66 2013 9025.94 2014 9344.03 2015 9664.12 2016 9902.79