Year Number of 1990 125.24 1991 131.1 1992 136.89 1993 143.11 1994 148.92 1995 154.9 1996 160.95 1997 167.19 1998 174.02 1999 181.3 2000 188.14 2001 194.27 2002 200.37 2003 207.67 2004 216.24 2005 225.49 2006 232.84 2007 240.48 2008 248.7 2009 258.26 2010 269.12 2011 278.33 2012 288.64 2013 299.15 2014 310.4 2015 322.06 2016 333.71