Year Number of 1990 317.1 1991 336.34 1992 362.19 1993 394.28 1994 428.19 1995 457.17 1996 475.81 1997 490.34 1998 502.28 1999 516.33 2000 534.88 2001 554.16 2002 568.35 2003 585.18 2004 603.11 2005 616.65 2006 627.73 2007 633.77 2008 641.73 2009 646.49 2010 653.88 2011 661.33 2012 671.59 2013 686.56 2014 701.83 2015 717.76 2016 736.59