Year Number of 1990 508.46 1991 522.04 1992 536.84 1993 552.07 1994 567.13 1995 582.05 1996 609.11 1997 636.42 1998 664.71 1999 694.55 2000 726.82 2001 737.64 2002 750.08 2003 762.96 2004 776.15 2005 790.09 2006 795.6 2007 801.73 2008 809.84 2009 819.59 2010 831.89 2011 834.51 2012 838.79 2013 843.87 2014 849.1 2015 854.11 2016 852.08