Year Number of 1990 53559.08 1991 53551.48 1992 57439.33 1993 65385.41 1994 68495.93 1995 63874.55 1996 57205.51 1997 51923.03 1998 49542.27 1999 51385.09 2000 52375.07 2001 51399.47 2002 51348.62 2003 50614.87 2004 49560.51 2005 49706.92 2006 46658.11 2007 45699.94 2008 45956.09 2009 44027.7 2010 44056.82 2011 42983.56 2012 41558.78 2013 41453.08 2014 41792.17 2015 42541.18 2016 43063.99