[] 1 1989 or 1990
[] 2 1985 to 1988
[] 3 1980 to 1984
[] 4 1970 to 1979
[] 5 1960 to 1969
[] 6 1950 to 1959
[] 7 1940 to 1949
[] 8 1939 or earlier
[] 9 Don't know