Sub-national carbon taxes exist in Canad and the US, among others. For example, Quebec introduced a carbon tax on certain fuels in 2007. In 2008, British Columbia followed with a tax that applies to the purchase or use of fuels within the province. The US state of California recently enacted a carbon tax at an initial rate of USD10 per ton of carbon content on coal, petroleum and natural gas. The tax will increase by USD10 each year, freezing when a mandated report by the Internal Revenue Service and the Department of Energy determines that CO2 emissions have decreased by 80 percent from 1990 levels.