However, Nigeria made the four notch jump without improving its score of 27 out of a possible 100 as recorded in 2017. Africa’s most populous country is tied with Kenya, Comoros, Guatemala and Mauritania. And it is ranked better than Cameroon put at 152nd. Botswana remains Africa’s most transparent country with a ranking of 34, followed by Namibia, Mauritius and Senegal. The United States slid to 22nd in the world from 18th last year, dropping out of the top 20 countries for the first time since 2011.