I want to know the answer to the following question:
What year did walkscore rank Boston the third most walkable city in the US?
All the background I'm provided with is that "As of 2015[update], Walk Score still ranks Boston as the third most walkable US city, with a Walk Score of 80, a Transit Score of 75, and a Bike Score of 70.". Is that enough to answer the question?
Answer: yes