Year Number of 1990 513.67 1991 535.01 1992 551.14 1993 561.92 1994 579.83 1995 585.93 1996 592.23 1997 591 1998 594.34 1999 602.93 2000 606.12 2001 618.61 2002 618.06 2003 619.2 2004 626.84 2005 626.97 2006 644.73 2007 658.42 2008 675.27 2009 674.02 2010 675.91 2011 688.05 2012 701.49 2013 712.79 2014 728.95 2015 758.97 2016 784.59