This week’s plummeting world oil prices are throwing into doubt financial stability in Venezuela, which relies on the commodity for most of its income.  Oil exporters from Russia to Iran are suffering with the lowest crude oil prices since June 2012. But few are as vulnerable as Venezuela, where a free-spending populist government had already been grappling with a recession, widespread shortages, and massive protests earlier this year.  The price of the Venezuelan barrel—heavier and more expensive to process than Middle East oil—fell to $77.65 on Friday, the lowest price since late 2010. The price drop was due to “ample” supply and weakening worldwide demand, the ministry said in its weekly oil price report Friday. Venezuelan oil has now tumbled nearly $15 since early September.