layer. Rhinoceros horns are used in traditional medicines in parts of Asia, and for dagger handles in Yemen and Oman. Esmond Bradley Martin has reported on the trade for dagger handles in Yemen. In Europe, it was historically believed that rhino horns could purify water and could detect poisoned liquids, and likely believed to be an aphrodisiac and an antidote to poison. It is a common misconception that rhinoceros horn in powdered form is used as an aphrodisiac or a cure for cancer in traditional Chinese medicine (TCM) as Cornu Rhinoceri Asiatici (犀角, xījiǎo, "rhinoceros horn"); no TCM text in history has ever mentioned such prescriptions. In TCM, rhino horn is sometimes prescribed for fevers and convulsions, a treatment not supported by evidence-based medicine: this treatment has been compared to consuming fingernail clippings in water. In 1993, China signed the CITES treaty and removed rhinoceros horn from the Chinese medicine pharmacopeia, administered by the Ministry of Health. In 2011, the Register of Chinese Herbal Medicine in the United Kingdom issued a formal statement condemning the use of rhinoceros horn. A growing number of TCM educators are also speaking out against the practice, although some TCM practitioners still believe that it is a life-saving medicine. Vietnam reportedly has the biggest number of rhino horn consumers, with their demand driving most of the poaching, which has risen to record levels. The "Vietnam CITES Management Authority" has claimed that Hanoi recently experienced a 77% drop in the usage of rhino horn, but National Geographic has challenged these claims, noticing that there was no rise in the numbers of criminals who were apprehended or prosecuted. South African rhino poaching's main destination market is Vietnam. An average sized horn can bring in as much as a quarter of a million dollars in Vietnam and many rhino range states have stockpiles of rhino horn. Horn trade International trade in rhinoceros horn has been declared illegal by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) since 1977. A proposal by Swaziland to lift the international ban was rejected in October 2016. Domestic sale of rhinoceros horn in South Africa, home of 80% of the remaining rhino population, was banned as of 2009. The ban was overturned in a court case in 2017, and South Africa plans to draft regulations for the sale of rhino horn, possibly including export for "non-commercial purposes".