Year Number of 1990 2214.03 1991 2322.18 1992 2435.75 1993 2558.03 1994 2682.6 1995 2808.24 1996 2941.35 1997 3073.12 1998 3217.73 1999 3360.2 2000 3488.45 2001 3607.24 2002 3710.09 2003 3813.25 2004 3921.17 2005 4036.67 2006 4151.57 2007 4265.89 2008 4386.21 2009 4534.19 2010 4686.26 2011 4830.62 2012 4984.41 2013 5151.17 2014 5328.21 2015 5524.71 2016 5725.97