Year Number of 1990 12973.42 1991 13173.68 1992 13354.77 1993 13559.21 1994 13660.11 1995 13808.05 1996 13885.17 1997 13951.54 1998 14046.44 1999 14122.36 2000 14138.15 2001 14316.58 2002 14587.67 2003 14849.39 2004 15032.51 2005 15319.35 2006 15509.37 2007 15739.52 2008 15965.14 2009 16094.08 2010 16344.85 2011 16500.28 2012 16806.26 2013 17039.36 2014 17225.34 2015 17312.55 2016 17347.54