Catholic Church in Ireland
In the 2016 Irish census 78.3% of the population identified as Catholic in Ireland; numbering approximately 3.7 million people. Unlike Catholics in the United States, Ireland has seen a significant decline from the 84.2% who identified as Catholic in the 2011 census.
Northern Ireland
At the 2011 census, 41.5% of the population identified as Protestant/non-Roman Catholic Christian, 41% as Roman Catholic, and 0.8% as non-Christian, while 17% identified with no religion or did not state one. The biggest of the Protestant/non-Roman Catholic Christian denominations were the Presbyterian Church (19%), the Church of Ireland (14%) and the Methodist Church (3%). In terms of community background (i.e. religion or religion brought up in), 48% of the population came from a Protestant background, 45% from a Catholic background, 0.9% from non-Christian backgrounds, and 5.6% from non-religious backgrounds.