Year Number of 1990 424.2 1991 443.75 1992 472.37 1993 502.6 1994 527.93 1995 546.3 1996 562.06 1997 575 1998 584.14 1999 600.41 2000 608.79 2001 626.5 2002 650.1 2003 675.81 2004 701.67 2005 721.57 2006 731.22 2007 745.72 2008 775.76 2009 816.7 2010 848.75 2011 871.97 2012 890.32 2013 899.37 2014 909.59 2015 948.5 2016 985.53