Main Question: Where can I find a table (or realistic formula) for isopropanol/water %vol/vol mixes and corresponding freezing temperature with public access?
Background: Trying to get the freezing point of my car windshield wash fluid.
What I have tried so far: Anti-freeze is may be ethanol or isopropanol. I got tables for ethanol/water %vol/vol and temperature, but could not find them for isopropanol. I learned that for ethanol the calculated (using simple formula) freezing temperature does not match the real one if using high concentrations, so this is likely true also for isopropanol, and why I am asking for this table.
Additional bonus question: is there a (household-practical) way to determine what was filled (and possibly even mixed during garage service): ethanol/isopropanal-based anti-freeze...?
(PS: wasn't sure about which forum, chemistry, physics... - please guide me if this question belongs somewhere else)