At ACS, 70 cents of the dollar is spent directly supporting the mission, which is lower than many non-profits and not all the 30 percent goes just to the CEO's salalry and employee retirement funds but they have a higher overhead with things like research facilities and equipment and supplies (wigs, prothetics, lab equipment, etc.) They still do a lot of good for cancer research, those suffering from cancer and their families. I used to be employed by them and I saw the good that they did daily. My only beef with them was they didn't fund a broader spectrum of cancers.
if you would like to fact check me, their I9 is available online for all the public to see.
Now the current large non-profit I work for is extremly proficient with roughly 93 cents on the dollar going towards the mission and is 97% volunteer run!