Year Number of 1990 335.77 1991 350.85 1992 367.08 1993 384.16 1994 402.12 1995 421.1 1996 437.27 1997 453.84 1998 470.13 1999 486.45 2000 503.16 2001 513.66 2002 523.7 2003 533.3 2004 543.04 2005 553.72 2006 563.81 2007 574 2008 585.96 2009 598.55 2010 612.15 2011 624.91 2012 638.43 2013 652.14 2014 666.42 2015 681.32 2016 698.65