From my own experience I can tell from all the airdrops that I know the top projects were only: Vite, Ontlogy, Dfinity. All others were shitcoins

You are right but what am not sure of is the percentage. I have quit participating in airdrops for sometime now due to the fact that majority of them will end up being either a scam or a worth less project. I got an airdrop reward I took part in the beginning of this year just last week and the value of all I got was 26 cents. It is so disheartening.