Year Number of 1990 5993.97 1991 5966.98 1992 5969.3 1993 6000.75 1994 6009.94 1995 6022.76 1996 6002.7 1997 5961.66 1998 5947.71 1999 5987.12 2000 5982.74 2001 5979.14 2002 5980.26 2003 5976.23 2004 5951.69 2005 5978.69 2006 6018.59 2007 6046.95 2008 6088.81 2009 6123.75 2010 6186.17 2011 6290.04 2012 6386.72 2013 6526.17 2014 6640.49 2015 6732.84 2016 6835.49