We do not have data for the lower end, but we do have some clue of where the higher end may be. We already have discovered a few systems where the mass fraction is very different from the Solar System’s (where planets take up ~0.134% of all system mass). Going by Wiki numbers, Gliese 876’s mass fraction within known planets is almost 1%, while Titawin and HR 8799 both have that number at almost 2%.