Concerned about the growing dependence of the nation's spy agencies on private contractors, top intelligence officials have spent months determining just how many contractors work at the C.I.A., D.I.A., F.B.I., N.S.A. and the rest of the spook alphabet soup. Now they have an answer. But they cannot reveal it, they say, because America's enemies might be listening. Steven Aftergood of the Project on Government Secrecy at the Federation of American Scientists, said the decision not to reveal the numbers was a sign of dysfunctional policies. "It reveals how confused the government is about what is really sensitive and what is not," Mr. Aftergood said. "What would Osama bin Laden do with the fraction of intelligence workers who are contractors? Absolutely nothing." The government's use of contractors has accelerated greatly during the Bush administration. Nowhere has the increase been more striking than in the spy agencies. The agencies have long fought efforts to make public their budgets and work force numbers. But not all officials have been punctilious about keeping the secrets. At a conference in 2005 ... a deputy director of national intelligence, let slip that the annual spy budget was $44 billion. Last year, John D. Negroponte, then the intelligence director, said in a speech "almost 100,000 patriotic, talented and hard-working Americans" work for the agencies. Why was Mr. Negroponte permitted to reveal that number? "It was an estimate," said Ross Feinstein, a spokesman for the current intelligence chief.

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