Year Number of 1990 498.63 1991 512.95 1992 481.39 1993 479.46 1994 540.44 1995 541.1 1996 494.61 1997 407.33 1998 381.56 1999 383.66 2000 383.35 2001 363.75 2002 361.33 2003 363.42 2004 366.62 2005 390.33 2006 378.9 2007 379.64 2008 369.88 2009 366.36 2010 377.6 2011 331.16 2012 336.93 2013 314.74 2014 325.42 2015 335.25 2016 336.27