For the past two decades, growth in the global economy spelled higher revenues for the Organization of Petroleum Exporting Countries. Not any more. The CHART OF THE DAY shows how last year was the first since 1993 that the value of OPEC’s total crude exports didn’t track the direction of global gross domestic product. The bottom panel shows how the group supplying about 40 percent of the world’s oil fetched lower average prices and also shipped fewer barrels year on year. Production among OPEC’s 12 members fell 2.5 percent to average 31.6 million barrels a day last year, data from OPEC’s Annual Statistic Bulletin ... (full story)