Take the following as truth: That number is high--the American Bar Association suggests 3% as a goal--but the drop appears significant and it's arguable that the firms reporting seem likely to be the ones donating the most.
Then the following statement: "Although the firms donating the most seem to be the ones that are reporting, there is no way to know for sure without further investigation." is true, false, or inconclusive?
Answer: Inconclusive