Since 2001, Congress has provided the Department of Defense (DOD) with about $808 billion in supplemental and annual appropriations, as of September 2008, primarily for military operations in support of the Global War on Terrorism (GWOT). DOD's reported annual obligations for GWOT have shown a steady increase from about $0.2 billion in fiscal year 2001 to about $162.4 billion in fiscal year 2008. The United States' commitments to GWOT will likely involve the continued investment of significant resources, requiring decision makers to consider difficult trade-offs as the nation faces an increasing fiscal challenge. The magnitude of future costs will depend on several direct and indirect cost variables and, in some cases, decisions that have not yet been made. DOD's future costs will likely be affected by the pace and duration of operations, the types of facilities needed to support troops overseas, redeployment plans, and the amount of equipment to be repaired or replaced. DOD compiles and reports monthly and cumulative incremental obligations incurred to support GWOT in a monthly Supplemental and Cost of War Execution Report. DOD leadership uses this report, along with other information, to advise Congress on the costs of the war and to formulate future GWOT budget requests. DOD reports these obligations by appropriation, contingency operation, and military service or defense agency. The monthly cost reports are typically compiled within the 45 days after the end of the reporting month in which the obligations are incurred. DOD has prepared monthly reports on the obligations incurred for its involvement in GWOT since fiscal year 2001.