At the time of the 2001 Census, 42% of the population identified themselves as being affiliated with the Church of Scotland, with 13% Roman Catholic and 28% with other Christian churches. Many of this last group belong to the Free Church of Scotland, known for its strict observance of the Sabbath. 11% stated that they had no religion. This made the Western Isles the Scottish council area with the smallest percentage of non-religious in the population. There are also small Episcopalian congregations in Lewis and Harris and the Outer Hebrides are part of the Diocese of Argyll and The Isles in both the Episcopalian and Catholic traditions.