The number of oil and gas rigs actively drilling in the U.S. added 1 to 544 during the past week, according to the latest survey reported Friday by Baker Hughes. During the week ended January 23, drilling rigs targeting crude oil in the U.S. rose by 1 to 411, while gas rigs were unchanged at 122, and 11 rigs remained classified as miscellaneous. The total rig count was down by 32, or 5.5%, from the same time a year ago.