From The Western Heritage by Donald Kagan, Steven Ozment, Frank M. Turner:
Despite proven cases of Catholic treason and even attempted regicide, she [Elizabeth] executed fewer Catholics during her forty-five years on the throne than May Tudor had executed Protestants during her brief five-year reign.
I tend to trust anything with Donald Kegan's name attached to it. I have read the estimates someplace, don't remember where, but will do some research to find them.
What are your sources? By the way, armed combart is not execution.
Shakespeare.