Because of the economic downturn, down, resulting in less trade with less transport. But if there is any economic good will have been exported, an increase in production is more.
Because if the economic decline resulting in a trade less with less transport. But if any economic good to be exported has increased by a factor of greater productivity.
Because the bad economy down, resulting in less trade transportation less. But if the economy will be increased exports is factor of production more and more.