U.S. companies announced 66,414 layoffs in July, the highest total in 16 months, a private consulting firm said Wednesday. After a first half of the year with announced job losses the lowest since 2000, international outplacement firm Challenger, Gray & Christmas, said July\'s announced layoffs rose 60 percent over the previous month and 59 percent over July 2010. The job cuts announced in the month were \"dominated by a flurry of large layoffs by a handful of private-sector employers,\" the firm said. Companies that announced layoffs in July Included Boston Scientific, Borders, Cisco Systems, Lockheed Martin and Merck & Co. Those five firms contributed 57 percent of the total, Challenger, Gray & Christmas said.