Trade costs among developing countries (“South-South") were the slowest to decline at the beginning of the period, but their decline gained momentum after the mid-2000s, outpacing the rest. They also show that trade costs are higher for services, mostly due to high variable costs. The first three categories capture the cost of delivering goods from suppliers to customers. They include the costs of transport, cargo loading, storage, port services and the costs of complying with customs procedures.