In what year did north Yemen and South Yemen unite?
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1990
1967
1967
1967
1967
1967
1967
1967
1991
1967
2015
1991
1967
2015
1990s
1991
1967
2015
1991
1970
1967
1960
2015
1991
1970
1967
1960
2015
1990s
1991
1970
1967
1960
2015
1991
1970
1967
1960
2015
1990s
1991
1970
1967
1960
2015
1962
1991
1970
1967
1960
2015
1990s
1962
1991
1970
1990 AD
1967
1960
2015
1962
1990s
1991
1970
1967
1960
2015
1962
1991
1970
1990 AD
1967
1960
2000
2015
1990s
1962
1991
1970
1967
1960
2000
2015
1990s
1962
1991
1970
1990 AD
1960
2000
2015
1963
1990.
1962
1986
1990s
1991
1970
1960
2000
2015
1963
1962
1990.
1986
1991
1970
1990 AD
1960
2000
2015
1990s
1963
1962
1986
1991
1970
1990.
1960
2000
2015
1963
1990s
1962
1986
1991
1970
1990 AD
1960
2000
2015
1963
1990.
1962
1986
1965
1990s
2000 AD
1991
1970
1960
2000
2015
1963
1987
1989
1962
1990.
1986
1965
1991
1970
1990 AD
1960
2000
2015
1990s
2011
1963
1987
1955
1989
1962
1986
1965
2000 AD
1970
1995
1990.
1979
1960
2000
2011
1963
1988
1987
1955
1961
1990s
1989
1962
1986