The collapse in oil prices is already a major cause of concern for countries heavily reliant on exports of the commodity. For some, it could be a matter of avoiding a severe recession. Here's why: For governments in oil-exporting countries to meet their spending commitments they need oil to remain above a certain price. With oil prices under $87 a barrel, countries that rely on high oil prices, including Venezuela, Russia, and Saudi Arabia, may have a reason to be concerned. This chart shows the price per barrel that the six most exposed countries need to meet their national budgets....