hmmm... % can means both purity or concentration (v/v). Most of the time purity is used for the stock solution whereas concentration is used when we dilute the stock solution.
So if you were to buy a new chemical such as isopropanol from manufacturer/distributor, mostly it means purity.
There are many grades of chemicals. Commonly, industrial grade not so pure, might have some impurities such as trace metal elements in it. Whereas analytical grade will be better as the spec of the metal impurities is much more tighter than industrial grade.

Industrial grade IPA mostly used for cleaning purpose, but for some industrial cleaning, they even use electronic grade IPA.
99% IPA (industrial grade) is good enough for average cleaning.
Correct me if I were wrong.

Well in lyn we can get around 99% pure ipa for a farely cheap price. That's the reason I mentioned the %purity here. no need to be too concern about the industrial grade ipa unless it is recycled ipa.