Laffer curve tax structure in 1997. Some have also cited Hauser's Law, which postulates that US federal revenues, as a percentage of GDP, have remained stable at approximately 19.5% over the period 1950 to 2007 despite changes in marginal tax rates over the same period. Others however, have called Hauser's Law "misleading" and contend that tax changes have had large effects on tax revenues. More recently, based on Laffer curve arguments, Kansas Governor Sam Brownback greatly reduced state tax rates in 2012. The state, which had previously had a budget surplus, experienced a budget deficit of about $200 million in 2012. Drastic
Ibn Khaldun scholars is increasingly common. Influential British historian and international affairs specialist Arnold J. Toynbee has called Ibn Khaldun's Muqaddimah "the greatest work of its kind." Ernest Gellner, once a professor of philosophy and logic at the London School of Economics, considered Khaldun's definition of government the best in the history of political theory. More moderate views on the scope of Ibn Khaldun's contributions have emerged. Arthur Laffer, for whom the Laffer curve is named, acknowledged that Ibn Khaldun's ideas, as well as others, precede his own work on that curve. A focus on understanding the nuances of Ibn Khaldun's contributions