The U.S. oil rig count this week dropped to the lowest level in over five years as energy firms stepped up the rate of idling rigs after one of the worst years in almost 30 years for drilling, data showed on Friday. Drillers removed 20 oil rigs in the week ended Jan. 8, bringing the total rig count down to 516, the least since April 2010, oil services company Baker Hughes Inc said in its closely followed report. That was the seventh decrease in the past eight weeks and brings the total rig count down to about a third of the 1,421 oil rigs operating in same week a year ago. In 2015, drillers idled a total of 963 oil rigs, the first annual cut since 2002 and the biggest annual decline since at least 1988, according to Baker Hughes.