Year Number of 1990 435.48 1991 444.95 1992 426.39 1993 448.36 1994 449.23 1995 443.42 1996 413.86 1997 386.17 1998 386.67 1999 374.56 2000 363.16 2001 375.3 2002 359.17 2003 364.87 2004 349.79 2005 366.12 2006 365.17 2007 367.25 2008 366.38 2009 319.34 2010 316.96 2011 315.33 2012 309.71 2013 304.23 2014 286.08 2015 287.78 2016 285.81