Year Number of 1990 1552.37 1991 1618.59 1992 1692.52 1993 1774.91 1994 1864.16 1995 1962.02 1996 2045.85 1997 2134.68 1998 2231.78 1999 2336.74 2000 2451.22 2001 2559.42 2002 2674.51 2003 2800.95 2004 2934.15 2005 3074.35 2006 3192.8 2007 3315.51 2008 3448.11 2009 3585.72 2010 3729.32 2011 3859.99 2012 3995.8 2013 4137.86 2014 4284.41 2015 4435.1 2016 4584.3