Year Number of 1990 602.03 1991 598.12 1992 597.34 1993 591.61 1994 594.16 1995 594.64 1996 596.86 1997 598.38 1998 590.08 1999 588.26 2000 587.09 2001 593.18 2002 605.39 2003 611.85 2004 618.43 2005 626.43 2006 649.28 2007 674.6 2008 718.86 2009 737.85 2010 759.67 2011 784.99 2012 804.21 2013 807.77 2014 821.08 2015 821.86 2016 830.64