Atheists did exist before Darwin, but they were not nearly as many, not nearly as well known, and not nearly as influential as until after Darwin.
I don't think there were any less than then now % wise, but like homosexuals in the 1950s, most Atheists back in Darwin's time were in the "Closet."
There is no better love between 2 people than mutual respect for each other WT Young, 2002
Who gave anyone the authority to call me an authority on anything. WT Young, 1969
Since Evolution is only ~90% correct it should be thrown out and replaced by Creation which has even a lower % of correctness. W T Young, 2008