The Potash Corporation of Saskatchewan, also known as PotashCorp, is a Canadian corporation based in Saskatoon, Saskatchewan. The company is the worlds largest potash producer and the third largest producers of nitrogen and phosphate, three primary crop nutrients used to produce fertilizer. At the end of 2011, the company controlled twenty percent of the worlds potash production capacity, two percent of nitrogen production capacity and five percent of phosphate supply. The company is part-owner of Canpotex, which manages all potash exporting from Saskatchewan. It also has a joint-venture with Sinochem named Sinofert. In late 2013, it was 60%-owned by institutional shareholders. In 2007, the CEO, William Doyle was by far the highest earning CEO in Canada, earning over $320 million. The company was created by the government of Saskatchewan in 1975. In 1989 it became a publicly traded company as the government of Saskatchewan sold off some of its shares, selling the remaining shares in 1990. The Saskatchewan potash industry began in the 1950s and 1960s. The government saw it as a promising new field and granted large subsidies to the new projects, mainly by American companies. However, this led to overproduction and when a global potash glut began in the late 1960s the industry almost collapsed. The Liberal government of the province introduced an emergency plan setting up quotas and a price floor in 1969. This plan was popular among the companies, which could now charge monopoly prices. The NDP government that was elected in 1971 in Saskatchewan was dissatisfied with this plan as the huge profits went to the companies rather than the government, and it wasn't sustainable in the long term. In 1974 the government passed a new potash regulation scheme, that included a reserve tax. This plan was resisted by the potash producers, and its constitutionality was challenged. Thus in 1975 the provincial government established the Potash Corporation of Saskatchewan as a government crown corporation.