Year Number of 1990 577.65 1991 657.5 1992 750.03 1993 853.2 1994 969.8 1995 1103.28 1996 1254.49 1997 1430.55 1998 1635.88 1999 1871.71 2000 2141.21 2001 2226.51 2002 2319.24 2003 2418.55 2004 2526.87 2005 2643.1 2006 2731.31 2007 2826.99 2008 2927.23 2009 3035.77 2010 3151.3 2011 3299.37 2012 3457.24 2013 3623.46 2014 3798.63 2015 3975.74 2016 4160.98