The D&B Industry Norms and key Business Ratios are made possible through over one million financial statements in the D&B Financial Information Base. This file consists of U.S. corporations, partnerships and proprietorships both public and privately owned, in all size ranges, and includes over 800 different lines of business as defined by the U.S. Standard industrial Classification (SIC) code numbers. The data is collected weekly, maintained daily, and constantly edited and updated.