Year Number of 1990 405.31 1991 421.19 1992 439.78 1993 460.68 1994 483.6 1995 508.67 1996 520.28 1997 534.12 1998 549.73 1999 566.54 2000 584.56 2001 588.29 2002 593.64 2003 600.15 2004 607.27 2005 615.25 2006 627.51 2007 640.53 2008 655.29 2009 671.67 2010 690.07 2011 708.97 2012 730.31 2013 752.94 2014 776.99 2015 802.3 2016 827.37