That represents a 13 percent rise over the previous year, and the soaring expense fell disproportionately on the private sector, where the costs to government contractors and other companies of meeting government-mandated security standards nearly doubled.
The figures are contained in the 2005 annual cost estimate from the Information Security Oversight Office, the government agency that oversees the national security classification system.
It includes the direct costs of deciding which information should be classified, and all the associated expenditure -- the system of personnel clearances, office security systems, special computer networks and other facilities -- incurred by both the government and industry.
In 2004, the total estimate was $8 billion, but of that just $823 million was incurred by the private sector. Those costs nearly doubled in 2005 to $1.6 billion, whereas government costs over the same period rose from about $7.2 billion to roughly $7.7 billion.
The figures were first reported by government transparency advocate Steven Aftergood, who runs the Federation of American Scientists Project on Government Secrecy.
As Aftergood pointed out, the figures do not include the estimated costs incurred by the CIA, because it has declared its cost data classified.