The Internal Revenue Service (IRS) is ready to help Americans pay their taxes, whether they want to or not. A bureau in the Department of the Treasury, the IRS is responsible for tax collection and tax law enforcement in its numerous forms. The agency collects 92% of the revenues that fund the US federal government. With an annual budget of about $13 billion, the IRS strives to fulfill its mission by helping taxpayers understand their obligations and by consistently and fairly enforcing tax laws. The agency is structured into four primary divisions: Wage and Investment, Large and International Business, Small Business and Self-Employed, and Tax-Exempt and Government Entities.