Some 2,900 people have left the National Church of Iceland in the last 12 months, according to figures from the National Registry.
Most of those people left the church during the last month due to a sex abuse scandal rocking the church. The scandal concerns a former bishop and has been widely reported in the media.
Some 550 people joined the Free Church in the last year and 170 people joined a different religious group.
The remaining 2,170 people are now without an officially registered religion – something which is unusual in Iceland, despite the fact that few people choose to attend church regularly.