Accountants will compute trend percents by when they Select a base period, assign each item in the base period statement a weight of 100%, and then express financial numbers from other periods as a percent of their base period number. Subtract the analysis period number from the base period number. Subtract the base period amount from the analysis period amount, divide the result by the analysis period amount, then multiply that amount by 100 Compare amounts across industries using Dun and Bradstreet. Compare amounts to a competitor