1970a	1970b	1971	1972a	1972b
1974**	1975a	1975b	1975c**	1977a**
1977b**	1977c	1978**	1979**	1980a**
1980b**	1980c**	1980d**	1984	1985
1987	1988	1989	1990*	1991