ByJohn S. McClenahen By now it's no secret that U.S. manufacturers are paying more for natural gas than they were only a year ago. For some companies during the current calendar quarter, the price could be as much as 139% higher than during the first three months of 2000, calculates the U.S. Energy Dept. Jerry Jasinowski, president of the National Assn. of Manufacturers, Washington, claims that during the past year price increases have reduced the profits of manufacturers using natural gas by roughly 14%. However, a just-released NAM survey of 737 manufacturers shows natural gas costs taking a surprisingly high toll on employees. Some 6% of firms responding have already laid off employees because of the price hikes, and 10% expect to lay off workers in the near future. Two-thirds of the manufacturers have reduced employee profit sharing; 36% have cut back on work hours, and 29% have reduced employee benefits.