Year Number of 1990 3529.08 1991 3692.56 1992 3853.98 1993 4008.95 1994 4174.75 1995 4363.36 1996 4575.37 1997 4849.78 1998 4990.67 1999 5085.3 2000 5171.31 2001 5103.89 2002 5065.3 2003 5073.99 2004 5066.26 2005 5042.89 2006 5195.53 2007 5317.02 2008 5462.14 2009 5610.77 2010 5783.91 2011 5912.77 2012 6060.85 2013 6219.5 2014 6377.35 2015 6573.83 2016 6772.87