Year Number of 1990 109.95 1991 112.44 1992 115.05 1993 117.7 1994 120.56 1995 123.68 1996 126.45 1997 129.47 1998 132.59 1999 135.97 2000 139.67 2001 142.73 2002 146.06 2003 149.64 2004 153.6 2005 158.01 2006 162.2 2007 166.68 2008 171.58 2009 176.9 2010 182.74 2011 187.59 2012 192.87 2013 198.07 2014 203.66 2015 209.67 2016 217.83