Gallup started collecting data in 1948 relating to religious trends in the United States. In that year the percentage of Americans stating they are Protestants was 69%, Catholics made up 22%, and no religion was at 2%. The high point in these studies for Protestants was in 1954 and 1956 when the percentage of Protestants reached 71%. The high point for Catholicism was in the 80's when it reached 28% and 29%. The Jewish populace has hovered pretty consistently between 2% and 4%. Mormonism wasn't really measured until the 80's and remains about 2%. Skip ahead to 2016's figures. Protestants are down to 37%. Catholics remain at 22%. Jewish is at 3%, Mormonism is at 2%, and non-specific Christian at 10%. No religion is at 18%. So, while the number for Catholics, Jews, and Mormons has remained fairly stabled over the 60+ years, the two major trends is the decline of Protestantism down from 71% to 37%, and the rise of no religion from 2% to 18% It appears given this data t...