Numbering them will be difficult. I think what we're opening our eyes to is that the corruption is not isolated and random, but rather a system of self-sustaining and proliferating cells by which every institution is subject to corruption. Just like cancer, answering your question with any precision will require autopsy. It seems that Q is designed to turn the tide by repairing & replacing as it goes, so even with good records we may never get a full answer.