Year Number of 1990 373.19 1991 367.13 1992 358.38 1993 353.28 1994 344 1995 335.91 1996 324.47 1997 316.46 1998 306.59 1999 299.35 2000 294.57 2001 292.07 2002 291.08 2003 281.63 2004 274 2005 271.35 2006 264.22 2007 259.94 2008 253.76 2009 250.19 2010 246.77 2011 246.27 2012 243.42 2013 240.1 2014 237.19 2015 239.57 2016 242.07