Question: When was the last time celtics won nba championship?
qaPairs: question: As of 2017, when was the last time the Celtics won the NBA championship?
answer: 2008
question: As of 2016, when was the last time the Celtics won the NBA championship?
answer: 2008
question: As of 2015, when was the last time the Celtics won the NBA championship?
answer: 2008