Each year domestic industry refines more than 170 million tons of crude oil with an average degree of refining of 71%. Approximately 50 million ions of furnace residual fuel oil is produced. This residual fuel oil is used as boiler fuel, except for a small amount which is exported (8-10 million tons in 2001). including approximately 13% burned directly at the refinery and the remainder burned in thermoelectric plants and boiler plants.