Year Number of 1990 278.41 1991 281 1992 290.53 1993 297.57 1994 304 1995 310.34 1996 318.36 1997 327.08 1998 323.11 1999 323.27 2000 325.97 2001 310.97 2002 308.55 2003 302.41 2004 300.81 2005 304.59 2006 302.46 2007 310.27 2008 310.1 2009 319.29 2010 329.75 2011 333.77 2012 338.21 2013 344.36 2014 363.07 2015 386.88 2016 400.58