Year Number of 1990 3431.69 1991 3539.12 1992 3660.9 1993 3790.68 1994 3924.53 1995 4065.22 1996 4365.53 1997 4700.89 1998 5073.74 1999 5495.93 2000 6001.48 2001 6248.9 2002 6513.95 2003 6803.03 2004 7116.98 2005 7463.8 2006 7607.98 2007 7820.49 2008 8071.39 2009 8359.79 2010 8692.36 2011 8932.77 2012 9210.53 2013 9520.42 2014 9860.43 2015 10232.67 2016 10599.86