Dictators dependent on oil reserves are set to feel the heat

Price movements as large and rapid as those that have upended oil markets since June 2014 are sure to cause pain to some and benefit others.
Though the pain tends to capture the most attention, the benefit is just as important — if not more so. The 70% drop in the price of a barrel of crude represents a colossal transfer of $3 trillion in annual income from oil producers to oil consumers.