The tax on childlessness (налог на бездетность) was imposed in the Soviet Union and other Communist countries, starting in the 1940s, as part of their natalist policies. Joseph Stalin's regime created the tax in order to encourage adult people to reproduce, thus increasing the number of people and the population of the Soviet Union. The 6% income tax affected men from the age of 25 to 50, and married women from 20 to 45 years of age. The tax remained in place until the collapse of the Soviet Union, though by the end of the Soviet Union, the amount of money which could be taxed was steadily reduced. Minister of Health Mikhail Zurabov and Deputy Chairman of the State Duma Committee for Health Protection Nikolai Gerasimenko proposed reinstating the tax in Russia in 2006, but so far it has not been reinstated. As originally passed and enforced from 1941 to 1990, the tax affected most childless men from 25 to 50 years of age, and most childless married women from 20 to 45 years of age. The tax was 6% of the childless person's wages, but it provided certain exceptions: those with children that died during World War II did not have to pay the tax, nor did war heroes that received certain awards. Also, many students were able to obtain an exemption from the tax, as did people who earned less than 70 rubles a month. Furthermore, those who were medically incapable to give birth were also exempt to this tax, and many single men fraudulently escaped the tax by claiming infertility and provided fake medical documentation. After 1990, the income exemption was increased to 150 rubles, meaning that the first 150 rubles of income for childless adults went untaxed. In 1991, the tax was changed to no longer apply to women, and in 1992, it was rendered irrelevant and inactive due to the collapse of the Soviet Union. In the 16th century, "bykowe" referred to a fee paid by the owner of a bull for mating cows. Later, during the 16th and 17th centuries, it also denoted a penalty for fathering an illegitimate child.