Consider chart wording when filter is enabled

<img width="724" alt="image" src="https://user-images.githubusercontent.com/3383539/170652736-8fc2955b-eed7-49f0-a582-0717ed3c042d.png">

When a user is filtering, should we change the wording here from '100% of question respondents' to something like '100% of filtered / selected respondents'?
@andypbrowne @caro-reops 