HOUSTON (Reuters) - US Gulf of Mexico oil and gas production is returning to near normal levels three days after Hurricane Michael made landfall on the Florida Panhandle, data from an offshore regulator showed , with oil output off 19 percent and natural gas production down less than 10 percent. The Bureau of Safety and Environmental Enforcement (BSEE) also said in an midday update that only one evacuated production platform was still unoccupied, down from 89 platforms on Wednesday. It can take several days after a storm passes to inspect platforms for damages, fully return crews and restore production after wells are shut-in ahead of a storm. Michael entered the Gulf as a tropical storm and quickly spun into a major hurricane, producing rough seas and winds of up to 155 miles per hour (250 kph) when it made landfall near Panama City, Florida, on Wednesday. As of midday on Saturday, the storm had left at least 18 dead in four Southeast US states and damages to communities in its path were estimated in the billions of dollars. It was one of the most powerful storms recorded in US history. The Gulf production still offline on Saturday morning represented 330,394 barrels per day of oil production and 247 million cubic feet per day of natural gas output, BSEE reported from a survey of 17 oil and gas producers. In all, Michael cost Gulf producers about 3.27 million barrels of oil this week. Offshore production in federal waters of the US Gulf of Mexico accounts for 17 percent of total US crude output and 5 percent of national natural gas production, according to the US Energy Information Administration. BSEE said its survey of producers showed that all drilling rigs and vessels that had been evacuated or moved to safer areas of the Gulf ahead of the storm were reoccupied and back at their drilling positions.