Percent of respondents mentioning they are inactive members in an environmental organization in the question: "Now I am going to read out a list of voluntary organizations; for each one, could you tell me whether you are a member, an active member, an inactive member, or not a member of that type of organization?". A higher score means that there are more inactive members in environmental organizations among the general population. A lower score implies that there are fewer inactive members in environmental organizations among the general population.