Maybe the absolutely worst are the 0.01% (or more likely, 1%). But the problem is more broad. There are different ways of corruption, making up word salads and fake results on one hand, or engaging in low effort repetitions with little to no questioning of the prevalent methodologies/theories of du jour, to fixing language in grant proposals/reports to get more money. When all these add up, I think 0.01% is likely the portion of the completely honest hard-working people in academia.