The Secretary of the Treasury ... is required annually to submit financial statements for the U.S. government to the President and the Congress. GAO is required to audit these statements. Certain material weaknesses in financial reporting and other limitations on the scope of our work resulted in conditions that continued to prevent us from expressing an opinion on the accompanying consolidated financial statements for the fiscal years ended September 30, 2006 and 2005. The federal government did not maintain effective internal control over financial reporting. While we are unable to express an opinion ... the following key items deserve emphasis. The U.S. government's total reported liabilities, net social insurance commitments, and other fiscal exposures continue to grow and now total approximately $50 trillion, representing approximately four times the Nation's total output (GDP) in fiscal year 2006, up from about $20 trillion, or two times GDP in fiscal year 2000. The retirement of thebaby boom" generation is [also] closer to becoming a reality with the first wave of boomers eligible for early retirement under Social Security in 2008. It seems clear that the nation's current fiscal path is unsustainable and that tough choices by the President and the Congress are necessary in order to address the nation's large and growing long-term fiscal imbalance. Other material weaknesses were the federal government's inability to: determine the full extent to which improper payments exist; identify and resolve information security control weaknesses; and effectively manage its tax collection activities.