The price of oil slumped below 72 dollars on Wednesday, its lowest level for more than 13 months, as recession fears raised concerns about a prolonged drop in energy demand, analysts said. The global financial crisis will give a vicious twist to an economic slowdown and is hitting world demand for oil, although the effect on emerging economies is unclear, OPEC said on Wednesday. The Organization of Petroleum Exporting Countries slashed its estimate of growth in demand this year and shaved its estimate for 2009, largely because of an "excessive" easing of demand in the United States, the single biggest energy market.