Year Number of 1990 303.27 1991 297.93 1992 301.82 1993 302.21 1994 308.96 1995 305.64 1996 292.63 1997 282.82 1998 280.13 1999 262.84 2000 243.9 2001 230.19 2002 225.03 2003 220.78 2004 217.4 2005 219.57 2006 217.99 2007 214.68 2008 210.09 2009 198.79 2010 195.74 2011 195.97 2012 194.94 2013 193.81 2014 195.22 2015 198.08 2016 199.63