Year scale 1-100 1970 55 1971 55 1972 55 1973 57.5 1974 57.5 1975 57.5 1976 57.5 1977 57.5 1978 57.5 1979 57.5 1980 57.5 1981 57.5 1982 57.5 1983 57.5 1984 57.5 1985 57.5 1986 57.5 1987 57.5 1988 57.5 1989 57.5 1990 60 1991 60 1992 60 1993 60 1994 60 1995 63.125 1996 65.625 1997 65.625 1998 65.625 1999 65.625 2000 65.625 2001 65.625 2002 65.625 2003 65.625 2004 68.125 2005 68.125 2006 68.125 2007 68.125 2008 68.125 2009 68.125 2010 68.125 2011 68.125 2012 68.125 2013 68.125 2014 68.125 2015 68.125 2016 68.125 2017 68.125 2018 68.125 2019 68.125 2020 68.125 2021 68.125 2022 68.125 2023 68.125