Unilever joined the Ad Age/-Bloomberg AdMarket 50 index following the purchase of index member Nabisco Group Holdings by R. J. Reynolds Tobacco Holdings. Its food marketing unit, Nabisco Holdings, was acquired by Philip Morris Cos. North America generated about 23% of third quarter Unilever sales (prior to completion of Unilever's purchase of Bestfoods). Unilever was ranked No. 33 in U.S. ad spending for 1999. In trading Friday, Unilever closed at $57.75, up 0.22% for the week.