Year Number of 1990 529.55 1991 542.3 1992 556.4 1993 572.14 1994 590.37 1995 611.96 1996 615.42 1997 620.91 1998 627.56 1999 635 2000 643.51 2001 648.97 2002 655.75 2003 663.73 2004 672.43 2005 683.51 2006 701.51 2007 720.25 2008 724.61 2009 753.52 2010 781.91 2011 811.66 2012 845.78 2013 880.98 2014 917.02 2015 954.67 2016 993.25