Year Percent 1987 40.84507 1988 46.2585 1989 45.13889 1990 45.33333 1991 31.25 1992 66.28686 1993 71.75015 1994 109.13051 1995 42.32678 1996 32.37055 1997 42.14259 1998 37.10791 1999 38.09631 2000 39.66721 2001 38.86857 2002 42.3997 2003 46.42211 2004 48.1823 2005 51.56769 2006 57.01668 2007 57.95058 2008 58.40358 2009 48.93413 2010 52.76446 2011 54.77407 2012 57.79832 2013 57.64138 2014 60.47015 2015 62.27023 2016 59.32536 2017 62.16803