thanks to the historic oil price increases of 2003–2008, opec revenues approximated an unprecedented us$1 trillion per year in 2008 and 2011–2014. beyond the opec countries, substantial surpluses also accrued to russia and norway, and sovereign wealth funds worldwide amassed us$7 trillion by 2014–2015. some oil exporters were unable to reap the full benefits, as the national economies of iran, iraq, libya, nigeria and venezuela all suffered from multi-year political obstacles associated with what economists call the "resource curse". most of the other large exporters accumulated enough financial reserves to cushion the shock when oil prices and petrodollar surpluses fell sharply again from an oil supply glut in 2014–2017.