Oil price dropped to below 100 dollars a barrel on Friday as investors were concerned about the oil demand and ongoing Greek debt talks. Data from the American Petroleum Institute showed that gasoline demand in U.S. dropped to lowest level in 10 years, due to warm winter and sluggish economy. The bearish data pressured on the oil price on Friday. Meanwhile, investors focused on the debt talks between Greece and its private creditors. The market had expected a voluntary write-down of Greek debt agreement might be reached. On economic front, the National Association of Realtors said U. S. existing home sales rose 5 percent to a 4.61 million annual rate in December, suggesting the housing market is improving. Light, sweet crude for February delivery lost 1.93 dollars, or 2 percent to settle at 98.46 dollars a barrel on the New York Mercantile Exchange. In London, Brent crude for March delivery was down 1.8 dollars to settle at 109.75 dollars a barrel.