Year Number of 1990 6351.97 1991 6372.44 1992 6375.46 1993 6442.61 1994 6383.52 1995 6315.8 1996 6120.06 1997 5921.81 1998 5921.28 1999 5824.15 2000 5816.1 2001 5915.83 2002 5949.11 2003 5803.66 2004 5788.18 2005 5773.98 2006 5733.86 2007 5788.39 2008 5874.22 2009 5926.23 2010 5966.76 2011 6045.43 2012 6165.16 2013 6196.78 2014 6164.74 2015 6287.53 2016 6403.87