The Department of Energy (Department), by its own estimate, spends about $217 million annually to operate over 50 separate nuclear material tracking systems and to perform other procedures necessary to maintain accountability over its nuclear material inventory. Because these systems are not fully integrated, obtaining comprehensive data about nuclear materials is inefficient. In addition to the many site-level systems, the Department also maintains the Nuclear Materials Management Safeguards System (NMMSS). Used since 1965, NMMSS comprises a major component of the Government's nuclear materials accounting system. It contains high-level, aggregate data on quantity, as well as individual transaction data on shipments of nuclear materials, both internal and external to the United States.