Year Number 1960 0 1961 0 1962 0 1963 -15 1964 -218 1965 -560 1966 -972 1967 -1398 1968 -1778 1969 -2212 1970 -2657 1971 -3118 1972 -3579 1973 -4038 1974 -4603 1975 -5174 1976 -5659 1977 -5957 1978 -5879 1979 -5130 1980 -4002 1981 -2864 1982 -2102 1983 -1988 1984 -1976 1985 -1956 1986 -1928 1987 -1901 1988 -1883 1989 -1848 1990 -1792 1991 -1751 1992 -1901 1993 485 1994 485 1995 485 1996 485 1997 485 1998 485 1999 485 2000 485 2001 485 2002 485 2003 485 2004 485 2005 485 2006 485 2007 485 2008 485 2009 485 2010 485 2011 485 2012 485 2013 485 2014 485 2015 485 2016 485 2017 485 2018 485 2019 -1487 2020 -742 2021 -742 2022 -1500 2023 -1500