Year Number of 1990 3686.39 1991 3836.93 1992 4000.87 1993 4200.19 1994 4370.92 1995 4569.21 1996 4721.68 1997 4861.85 1998 5021.87 1999 5234.01 2000 5375.85 2001 5532.92 2002 5702.33 2003 5866.55 2004 6021.04 2005 6170.09 2006 6334.01 2007 6503.94 2008 6705.4 2009 6934.85 2010 7186.65 2011 7441.07 2012 7704.63 2013 7959.26 2014 8170.49 2015 8247.26 2016 8389.9