Final answer:
The support for the environmental movement in the 1960s-1980s and the participation in political activities are relevant factors to consider when discussing the percentage of Americans in environmental organizations.
Step-by-step explanation:
A specific percentage of Americans who report being in an environmental organization was not mentioned in the provided information. However, the question can be addressed by discussing the support for the environmental movement and participation in political activities in the United States:
The growing environmental movement in the 1960s through the 1980s was most likely supported by various groups, including environmental organizations, activists, and concerned citizens. This movement aimed to raise awareness about environmental issues, advocate for conservation and protection of natural resources, and influence government policies for sustainable development.
As for participation in politics, a survey conducted in 2018 revealed that almost 70 percent of American adults had participated in some type of political action in the past five years. This includes activities such as signing petitions, expressing opinions on social media, contacting elected representatives, contributing money to campaigns, attending local government meetings or political rallies, and working or volunteering for a campaign.