SALT LAKECITY (AP) – A new informal survey by a Utah-based polygamy advocacy group estimates 38,000 people believe in or are living the practice – an increase of about 1,000 in about two years.

The survey by Principle Voices includes adults and children in polygamous and monogamous families who consider themselves fundamentalist Mormons. The last survey was conducted in 2007.

Principle Voices co-founder Anne Wilde says the largest number of polygamists are independents – about 15,000 – unaffiliated with any organized church.

The southern Utah-based Fundamentalist Church of Jesus Christ of Latter Day Saints was the largest organized group with about 10,000 members.

Survey data is collected from both leaders of organized groups and individuals across the Intermountain West.