Year Number of 1990 225.98 1991 238.61 1992 250.73 1993 263.95 1994 278.11 1995 293.05 1996 309.04 1997 324.31 1998 343.07 1999 362.27 2000 378.42 2001 398.31 2002 422.48 2003 448.56 2004 478.43 2005 512.8 2006 535.82 2007 561.45 2008 588.12 2009 620.26 2010 660.85 2011 670.44 2012 689.1 2013 699.79 2014 725.29 2015 763.91 2016 810.17