Year Number of 1990 801.15 1991 870.74 1992 971.51 1993 1077.37 1994 1183.51 1995 1280.2 1996 1382.72 1997 1504.25 1998 1648.2 1999 1809.58 2000 1946 2001 2075.35 2002 2192.82 2003 2319.11 2004 2414.92 2005 2552.94 2006 2762.95 2007 2957.84 2008 3172.46 2009 3410.02 2010 3626.56 2011 3775.86 2012 3893.21 2013 3931.26 2014 4012.53 2015 4102.67 2016 4210.88