Year Number of 1990 35001.69 1991 36913.03 1992 38760.34 1993 40379.04 1994 41911.27 1995 43701.89 1996 45133.54 1997 46507.2 1998 47856.17 1999 49556 2000 51326.97 2001 53077.72 2002 54868.8 2003 56730.8 2004 59100.84 2005 61621.63 2006 63740.15 2007 66247.26 2008 68465.22 2009 69938.65 2010 71827.23 2011 73134.22 2012 74081.31 2013 74701.97 2014 74192.11 2015 74899.69 2016 75747.65