I don' think i have seen vatlhvI' in the notes. Does it really mean percent or 1/100? In the latter case, could I use cha' wejvI' to say 2/3 and so on?
Not as far as we know, though there has been speculation on that. vI' normally represents the decimal point where it is not attached to a number, but used as a separate word in numbers like vaghvatlh loSmaH wej vI' pagh wa' cha' ("543.012"). Note that numbers after the vI' are read in order rather than by powers of ten or fractions. We don't know of a good way to represent fractions and some klingonists have speculated that perhaps vI' could be used for that in the model of vatlhvI'. However we do not have confirmation of that and other klingonists might strongly object.