Question: When did the voting age change from 21 to 18?
Answer: 1970s
Disambiguated annotations:
qaPairs: question: When did the debate begin to lower the voting age from 21 to 18?
answer: during WW II
question: By what date did some states change the voting age from 21 to 18?
answer: 1968
question: In what year was a voting age over 18 outlawed?
answer: 1971