When fuel prices go up, they go up quickly, but when they fall back, if they fall back at all, it’s a slow process. A new report on gasoline and the petroleum industry from the Federal Trade Commission outlines some of the causes of this “rockets and feathers” phenomenon and other fuel-price trends.

The report examines a broad range of factors that influence what Americans pay at the gasoline pump, and concludes that worldwide crude-oil prices are by far the key driver behind gas price swings, and global demand is the major force behind crude prices.