Year Number of 1990 268.06 1991 285.49 1992 296.87 1993 311.82 1994 336.2 1995 348.74 1996 362.28 1997 387.94 1998 421.35 1999 462.36 2000 511.48 2001 542.41 2002 579.42 2003 609.5 2004 637.81 2005 655.21 2006 676.07 2007 692.7 2008 710.11 2009 738.32 2010 766.71 2011 776.12 2012 789.49 2013 790.72 2014 797.22 2015 808.1 2016 818.67