Year Number of 1990 2519.47 1991 2525.78 1992 2655.97 1993 2560.82 1994 2676.13 1995 2599.15 1996 2803.48 1997 3191.27 1998 3336.83 1999 3534.41 2000 3831.06 2001 3821.28 2002 3917.02 2003 4043.13 2004 4136.68 2005 4252.74 2006 4341.64 2007 4271.26 2008 4179.98 2009 4175.45 2010 4219.82 2011 4206.55 2012 4122.8 2013 4156.79 2014 4301.55 2015 4364.3 2016 4395.6