New study puts Nigeria 2nd most religious country & 4th among 'most widespread use of Marijuana in the world'

According to a new research carried out by US based researcher, Conrad Hackett, who works with Pews researcher, a US based non-partisan research group, Nigeria is ranked the 2nd most religious country after Pakistan and is also ranked the 4th country with the most widespread use of illegal substance, Marijuana, in the world. Is this really our reality or it is contestable?