Year Number of 1990 391.66 1991 404.02 1992 416.14 1993 425.91 1994 461.22 1995 463.71 1996 452.93 1997 424.88 1998 426.76 1999 437.18 2000 434.91 2001 427.97 2002 419.78 2003 419.25 2004 418.55 2005 407.1 2006 413.59 2007 421.74 2008 429.27 2009 435.95 2010 445.68 2011 438.4 2012 439.44 2013 442.14 2014 456.03 2015 445.1 2016 432.72