Year Number of 1990 5242.1 1991 5599.5 1992 5990.84 1993 6419.99 1994 6895.73 1995 7425.85 1996 7872.97 1997 8358.49 1998 8893.02 1999 9453.03 2000 10042.03 2001 10559.33 2002 11106.54 2003 11743.37 2004 12433.19 2005 13194.03 2006 13907.46 2007 14673.83 2008 15549.08 2009 16494.79 2010 17523.7 2011 18585.15 2012 19731.53 2013 20941.69 2014 22248.06 2015 23667.97 2016 25183.3