The number of rigs drilling for oil in the United States fell by 10 this week as low crude prices continued to threaten energy company revenues. The oil rig count dropped to 1,536 in the week to Dec. 19, the least since May, according to data from oil services firm Baker Hughes on Friday. The number of oil rigs has declined in seven of the last 10 weeks since hitting a record high of 1,609 in mid October, as a 50 percent drop in oil prices since the summer begins to take its toll on drilling projects. In the prior week ended Dec. 12, oil rigs declined by 29, the biggest weekly drop in two years. Energy traders have been watching rig data to see if the steep price drop was prompting oil drillers to cut back on the number of rigs. Some analysts however […]