Ambulance fees could rise by 40 percent in Sharon for the second time in two years. At its Jan. 29 meeting, the Board of Selectmen plans to discuss the increase, which would match one it approved in 2011. Fire Chief James Wright said in an interview that rising rates are driven by the cost of doing business. Even with the increase two years ago, the town subsidizes ambulance service, which could not operate if it relied on fees, he said. Although rates vary depending on the services, Wright said Sharon’s rate for basic life support in an emergency is $748.89. A 40 percent hike would make it $1,048.45. About 95 percent of people who use the ambulance service have some form of private or public health insurance, he said.