Well, Usually it cost a lot for them to get education... and they are a more traditional based society... so men are more likely to be literate for work as opposed to girls.
In africa,for social,cultural andeconomic issues males have had access to better education opportunities than females.Tribalism,religious influences and social standards contribute significantly for the gap in the literacy rate.
After the war, the legislature granted several of these men their freedom as a reward for faithful service. African Americans also served as gunners, sailors on privateers and in the Continental Navy during the Revolution.