Current standard sizes of U.S. paper are a subset of the traditional inch sizes referred to below. "Letter", "legal", "ledger", and "tabloid" are by far the most commonly used of these for everyday activities. The origin of the exact dimensions of "letter" size paper (8½ in × 11 in, 215.9 mm × 279.4 mm) are lost in tradition and not well documented. The American Forest and Paper Association argues that the dimension originates from the days of manual paper making, and that the 11 inch length of the page is about a quarter of "the average maximum stretch of an experienced vatman's arms." However, this does not explain the width or aspect ratio.