Suppose U.S. drivers purchased $70 billion ofExxonMobil-produced gasoline during a recentyear, withone-half purchased directly fromExxonMobil-owned gas stations andone-half from independent(or third-party) gas stations. Suppose further that ExxonMobil purchased the oil(which it refined intogasoline) from foreign producers for $24 billion and that it receives 60 percent of the sales revenue that independent stations generate from selling ExxonMobil gasoline.