Since the plunge in oil prices in late 2014 and early 2015, petroleum exporting countries such as Iran, Russia and Venezuela have struggled with ballooning budget deficits, weakening currencies and the spectre of social unrest.

The picture is far brighter in Mexico. Despite being a major oil exporter – in 2013, oil industry earnings accounted for 32% of government revenues – Mexico remains a darling of emerging market investors. The country has held onto its long-term local currency rating of A