Year Number of 1990 1931.37 1991 2002.76 1992 2087.65 1993 2152.06 1994 2220.81 1995 2289.48 1996 2365.37 1997 2455.94 1998 2613.69 1999 2933.2 2000 3248.29 2001 3532.65 2002 3795.96 2003 4044.69 2004 4137.08 2005 4275.29 2006 4448.22 2007 4557.41 2008 4637.64 2009 4741.03 2010 4860.4 2011 4946.92 2012 5019.08 2013 5108.57 2014 5196.91 2015 5253.61 2016 5297.33