In 1863, the government monopoly on vodka production was repealed, causing prices to plummet and making vodka available even to low-income citizens. The taxes on vodka became a key element of government finances in Tsarist Russia, providing at times up to 40% of state revenue. By 1911, vodka comprised 89% of all alcohol consumed in Russia. This level has fluctuated somewhat during the 20th century but remained quite high at all times. The most recent estimates put it at 70% (2001). Today, some popular Russian vodka producers or brands are (amongst others) Stolichnaya and Russian Standard. During the late 1970s, Russian culinary author William Pokhlebkin compiled a history of the production of vodka in Russia, as part of the Soviet case in a trade dispute; this was later published as A History of Vodka. Pokhlebkin claimed that while there is a wealth of publications about the history of consumption and distribution of vodka, virtually nothing had been written about vodka production. One of his assertions was that the word "vodka" was used in popular speech in Russia considerably earlier than the middle of the 18th century, but the word did not appear in print until the 1860s. Pokhlebkin's sources were challenged by David Christian in the Slavic Review in 1994. Christian criticized the lack of valid references in Pokhlebkin's works stating that his work has an obvious pro-Russian bias. Pokhlebkin is also known for his Pan-Slavic sympathies under the leadership of Russia and sentiments that, in David Christian's opinion, discredit most of his work, especially his History of Vodka. Sweden Up until the 1950s, vodka was not used as a designation for Swedish distilled beverages, which were instead called brännvin ("burn-wine"), the word having the same etymology as the Dutch Brandewijn, which is the base for the word brandy. This beverage has been produced in Sweden since the late 15th century, although the total production was still small in the 17th century. From the early 18th century, production expanded, although production was prohibited several times, during grain shortages. Although initially a grain product, potatoes started to be used in the production in the late 18th century and became dominant from the early 19th century. From the early 1870s, distillery equipment was improved. Progressively from the 1960s, unflavoured Swedish brännvin also came to be called vodka. The first Swedish product to use this term was Explorer Vodka, which was created in