We are given that among the 1018 respondents, 255 said that they did not believe in evolution. And we are asked to find the percentage of respondents who said that they did not believe in evolution.
In order to calculate the percentage we need to divide the number of respondents who said that they did not believe in evolution by the total number of respondents = 255/1018 = 0.2505 = 25.05%
Hence we can say that 25.05% respondents said that they did not believe in evolution.