A card reader displays a thumb print of a voter as an electoral officer scans the thumb print of a voter at a polling unit at the start of general elections in Daura

A card reader displays a thumb print of a voter as an electoral officer scans the thumb print of a voter at a polling unit at the start of general elections in Daura, northwest Nigeria, March 28, 2015. Nigerians went to the polls on Saturday in what looks set to be the first genuine electoral contest since the end of military rule in 1999, in which an opposition candidate has a fighting chance of unseating the incumbent, President Goodluck Jonathan. REUTERS/Akintunde Akinleye