This is difficult to answer to give an exact % of the bluffs in general.
Optimally the bluff to value ratio should be similar to the pot
odds we are offering with our bet sizing to make the villian indifferent between calling and folding, but of course this is extremely hard to figure out on the fly.
We will need to bluff at least some of the time, otherwise we become easy to play against.
If we are rarely ever bluffing, our opponents can expolit us by over-folding and we will fail to get value when we need it.
If we bluff too much, our opponents will be able to exploit us by calling down lighter and our bluffs will fail to have fold
equity.
This is why we must incorperate some bluffs, but not too much into our game so we make it hard for the villian to know of we are bluffing or value betting and force him to make a mistake. We want him to sometimes think we are blufffing to call our big hands, and we want him to sometimes fold to us when we are bluffing.