Year Number of 1990 452.43 1991 461.29 1992 462.06 1993 485.2 1994 496.84 1995 512.74 1996 520.22 1997 540.68 1998 558.76 1999 556.81 2000 574.77 2001 593.1 2002 617.38 2003 638.44 2004 659.7 2005 680.72 2006 695.7 2007 711.1 2008 729.25 2009 749.13 2010 772.89 2011 792.43 2012 813.46 2013 843.06 2014 870.32 2015 901.07 2016 931.82