Fewer people would identify as atheist because people were not willing to share alternative religious beliefs publicly.
In the late 17th century, noted empirical philosopher John Locke promoted religious toleration ... but by religious toleration he meant toleration between Catholics and Protestants. But atheists were not to be tolerated, according to Locke (and most others in that era). Locke argued in his Letter Concerning Toleration (1789): "Those are not at all to be tolerated who deny the being of a God. Promises, covenants, and oaths, which are the bonds of human society, can have no hold upon an atheist. The taking away of God, though but even in thought, dissolves all."