Year Number of 1990 4538.94 1991 4665.69 1992 4778.78 1993 4875.09 1994 4956.37 1995 5051.87 1996 5150.57 1997 5239.06 1998 5341.12 1999 5448.04 2000 5522.12 2001 5550.09 2002 5577.93 2003 5698.87 2004 5821.07 2005 5918.77 2006 5926.67 2007 5964.1 2008 6053.49 2009 6076.42 2010 6070.21 2011 6123.43 2012 6127.09 2013 6055.65 2014 6008.41 2015 5990.82 2016 5991.17