I am willing to bet that the percentages would be even lower among UK scholars. Now it is certainly true and accepted that he did not write or contributed little to several plays (Henry VI, Titus Andronicus, Pericles), but that is a different question.
So this question made me wonder how technical/specific to be. Could it be worded differently? For example, by specifying it’s about non-avian dinosaurs.
That said, I can see how it might be debatable, so I changed the question to one that is not.