Year Number of 1990 475.01 1991 508.97 1992 563.13 1993 568.45 1994 600.91 1995 604.5 1996 606.24 1997 596.35 1998 587.85 1999 586.74 2000 586.86 2001 580.86 2002 592.01 2003 587.12 2004 593.69 2005 596.68 2006 587.66 2007 589.89 2008 594.45 2009 593.1 2010 602.13 2011 601.24 2012 610.75 2013 627.52 2014 649.31 2015 649.59 2016 653.11