Service economy growth seen

Changing demographics ensure the continued growth of the ''service economy'' in the United States, says Arthur D. Little Inc. of Cambridge, Mass. The service economy - ranging from insurance to hotels to software writing - accounts for 58 percent of the US gross national product and 54 percent of the work force, says consultant Carol Gibbons Krauss. Reasons for the growth: The baby-boom generation is moving into prime spending years (ages 35-44); computerization is bringing about new services such as automatic banking; and specialization is boosting the number of outside contractors required for tasks such as building maintenance.