Year Number of 1990 3570.37 1991 3681.87 1992 3802.89 1993 3933.7 1994 4072.93 1995 4225.65 1996 4447.41 1997 4687.66 1998 4947.78 1999 5226.69 2000 5531.73 2001 5754.89 2002 5997.47 2003 6258.8 2004 6535.59 2005 6834.56 2006 7025.74 2007 7220.69 2008 7439.19 2009 7669.03 2010 7918.07 2011 8128.98 2012 8354.71 2013 8594.37 2014 8847.8 2015 9113.11 2016 9397.39