Year Number of 1990 50766.43 1991 50873.54 1992 55245.71 1993 64424.84 1994 68312.18 1995 63523.28 1996 56523.24 1997 51101.51 1998 48760.52 1999 51050.71 2000 52379.23 2001 51646.11 2002 51832.33 2003 51117.11 2004 49954.94 2005 50096.78 2006 46695.04 2007 45595.63 2008 45885.93 2009 43793.89 2010 43774.34 2011 42558.26 2012 41006.2 2013 40893 2014 41256.39 2015 41973.13 2016 42402.73