In an attempt to combat the grade inflation prevalent at many top US institutions, Princeton began in the autumn of 2004 to employ guidelines for grading distributions across departments. Under the new guidelines, departments have been encouraged to re-evaluate and clarify their grading policies. The administration suggests that, averaged over the course of several years in an individual department, A-range grades should constitute 35% of grades in classroom work, and 55% of grades in independent work such as Senior Theses. These guidelines are enforced by the academic departments. Since the policy's inception, A-range grades have declined significantly in Humanities departments, while remaining nearly constant in the Natural Science departments, which were typically at or near the 35% guideline already.