Year Number of 1990 301.71 1991 306.99 1992 314.31 1993 325.19 1994 337.07 1995 345.63 1996 345.24 1997 351.12 1998 375.6 1999 376.87 2000 383 2001 396.46 2002 412.82 2003 437.28 2004 461.2 2005 484.18 2006 510.16 2007 534.67 2008 564.73 2009 593.71 2010 622.25 2011 649.77 2012 678.36 2013 709.31 2014 741.65 2015 775.05 2016 803.67