Year Number of 1990 565.52 1991 582.17 1992 582.7 1993 588.23 1994 601.71 1995 609.15 1996 616.08 1997 607.87 1998 612.89 1999 621.65 2000 622.44 2001 638.14 2002 642.77 2003 648.03 2004 658.39 2005 658.13 2006 667.67 2007 673.58 2008 677.31 2009 677.9 2010 680.42 2011 687.31 2012 697.33 2013 699.15 2014 711.55 2015 728.77 2016 745.5