Some Heathen communities have formalized such values into an ethical code, the Nine Noble Virtues (NNV), which is based largely on the "Hávamál" from the "Poetic Edda". This was first developed by the founders of the UK-based Odinic Rite in the 1970s, although it has spread internationally, with 77% of respondents to a 2015 survey of Heathens reporting its use in some form. There are different forms of the NNV, with the number nine having symbolic associations in Norse mythology. Opinion is divided on the NNV; some practitioners deem them too dogmatic, while others eschew them for not having authentic roots in historical Germanic culture, negatively viewing them as an attempt to imitate the Judeo-Christian Ten Commandments. Their use is particularly unpopular in Nordic countries, and has been observed declining in the United States.