Year Number of 1990 521.26 1991 530.44 1992 498.05 1993 494.37 1994 547.76 1995 545.89 1996 498.58 1997 413.49 1998 386.92 1999 385.82 2000 383.03 2001 362.31 2002 359.23 2003 360.16 2004 363.15 2005 383.86 2006 373.85 2007 375.57 2008 367.4 2009 365.19 2010 375.5 2011 334.25 2012 339.23 2013 319.34 2014 328.59 2015 337.48 2016 338.1