Year Number of 1990 487.29 1991 498.18 1992 483.87 1993 508.94 1994 507.26 1995 498.68 1996 463.42 1997 432.61 1998 431.77 1999 418.78 2000 408.01 2001 423.34 2002 411.89 2003 424.64 2004 416.34 2005 441.89 2006 450.35 2007 464.05 2008 476.06 2009 425.09 2010 426.33 2011 428.56 2012 429.14 2013 429.88 2014 416.09 2015 427.25 2016 436.45