The U.S. oil-rig count fell by eight to 644 in the latest reporting week, the third-straight decline after six consecutive weeks of increases, according to Baker Hughes Inc. BHI -3.29 % The number of U.S. oil-drilling rigs, which is viewed as a proxy for activity in the oil industry, has fallen sharply since oil prices started falling last year. The rig count dropped for 29 straight weeks before climbing modestly in recent weeks. Despite recent increases, there are still about 50% fewer rigs working since a peak of 1,609 in October. According to Baker Hughes, the number of gas rigs rose by two to 198. The U.S. offshore rig count was 31 in the latest week, unchanged from last week and down 31 from a year earlier. For all rigs, including natural gas, the week’s total was down six to 842.