Year scale 1-100 1970 49.375 1971 49.375 1972 49.375 1973 49.375 1974 49.375 1975 49.375 1976 49.375 1977 49.375 1978 49.375 1979 49.375 1980 49.375 1981 49.375 1982 49.375 1983 49.375 1984 49.375 1985 49.375 1986 49.375 1987 49.375 1988 52.5 1989 52.5 1990 52.5 1991 52.5 1992 52.5 1993 52.5 1994 52.5 1995 57.5 1996 57.5 1997 57.5 1998 63.75 1999 63.75 2000 63.75 2001 63.75 2002 63.75 2003 63.75 2004 63.75 2005 63.75 2006 66.25 2007 66.25 2008 66.25 2009 66.25 2010 66.25 2011 66.25 2012 66.25 2013 66.25 2014 66.25 2015 66.25 2016 66.25 2017 68.75 2018 71.875 2019 71.875 2020 74.375 2021 74.375 2022 74.375 2023 74.375