text: Until the mid-1950s coal was still the world's foremost fuel, but after this time oil quickly took over. Later, following the 1973 and 1979 energy crises, there was significant media coverage on the subject of oil supply levels. This brought to light the concern that oil is a limited resource that will eventually run out, at least as an economically viable energy source. Although at the time the most common and popular predictions were quite dire, a period of increased production and reduced demand in the following years caused an oil glut in the 1980s. This was not to last, however, and by the first decade of the 21st century discussions about peak oil had returned to the news.
  Today, about 90% of vehicular fuel needs are met by oil. Petroleum also makes up 40% of total energy consumption in the United States, but is responsible for only 2% of electricity generation. Petroleum's worth as a portable, dense energy source powering the vast majority of vehicles and as the base of many industrial chemicals makes it one of the world's most important commodities.
  As of 2010s, massive hydraulic fracturing are being applied on a commercial scale to shales in the United States, Canada, China and others.
  The top three oil producing countries are Saudi Arabia, Russia, and the United States in 2006. However, figures from 2021 shows that the United States has surpassed (18.8 million barrel per day) both Russia (10.8) and Saudi Arabia (10.8) by a wide margin. About 80% of the world's readily accessible reserves are located in the Middle East, with 62.5% coming from the Arab 5: Saudi Arabia (12.5%), UAE, Iraq, Qatar and Kuwait.  However, with high oil prices (above $100/barrel), Venezuela has larger reserves than Saudi Arabia due to its crude reserves derived from bitumen.