Year Number of 1990 5113.29 1991 5055.37 1992 4951.2 1993 4860.6 1994 4765.62 1995 4724.13 1996 4668.63 1997 4594.9 1998 4548.56 1999 4508.02 2000 4476.24 2001 4418.25 2002 4414.88 2003 4392.61 2004 4356.82 2005 4294.1 2006 4234.09 2007 4191.05 2008 4166.34 2009 4177.19 2010 4155.41 2011 4075.15 2012 4011.93 2013 3926.68 2014 3817.31 2015 3691.99 2016 3670.99