When, Why, How did the Northeast US lose Protestant Christian majority?

The northeast US was settled by the Puritans and was "New England" once. The South particularly Florida and Louisiana was held by the Spanish and French. How did it happen that the South is now largely Protestant Christian and the Northeast now predominantely no longer Protestant Christian? The Northeast US now seems to be Catholic and this ratio is being aggravated. How did this happen? What can we do to help the Catholics embrace the Anglo Saxon Protestant Christian faith of the settlers and founders of the US? Is there a way of seeing historical demographic data by religious affiliation? What can the incoming minorities and the legal entrants and law abiding immigrants do to embrace the faith of the larger society? What can they do to embrace Protestant Christianity and Capitalism and all the good things which arose from the Protestant ethic?