ByJohn S. McClenahen Business activity in the service sector of the U.S. economy continued to increase in March, although growth was less than in February, reports the Institute for Supply Management (ISM), Tempe, Ariz. ISM's non-manufacturing index was 57.3% in March, compared with 58.7% in February. March's mark, however, was the second strongest showing since the 59.5% posted in November 2000. A figure above 50% indicates the non-manufacturing sector is growing; a figure below 50% generally signals contraction. Ten of the industry groups included in the index showed growth in March, five contracted and two were unchanged. With a relatively strong showing in new orders, one of the index 's nine components, and a continued increase in order backlogs, another index component, "it appears that the non-manufacturing economy may continue to grow in the coming months," says Ronald G. Kauffman, chairperson of ISM's non-manufacturing business survey committee and coordinator of the purchasing and supply-management program at the University of Houston-Downtown.