I am always seeing estimates of the percentage of stars which might have a planetary system surrounding them. (Current estimates range from 20% to 50%) I think they are all wrong.
I suspect it will eventually be realized that star formation includes planet formation just as surely as dropping a big rock into sloppy mud creates a surrounding pattern of splatter. Planets may be considered almost a part of a star. Beyond the chromosphere and the corona is the "planetsphere".
So, I strongly suspect the percentage of stars with a planetary system is 100%- with the possible exception of some stars which went through some cataclysmic event that stripped them away from their planets. (What percentage of humans have a head?)
Now, how many of those stars have a planet (or more) where life develops, and how likely is it for sapience to arise in those biospheres? The answers may turn out to be just as obvious.