Which groups have the highest knowledge levels? It turns out that it’s atheists and agnostics (an average of 20.9 correct answers out of 32) . . . Interestingly, atheists and agnostics (6.7 correct answers) score significantly higher than Christians (6.0) on the 12 questions that cover knowledge of Christianity and the Bible.
"The Recent Pew Research Center survey of American’s knowledge about religion shows widespread ignorance. The study asked 32 mostly relatively basic multiple choice questions about various religions (including a few on religion and public life)."