I think it is impossible job to achieve accurate data across so many countries, you can rely on some EU wide data from their datasets but they don§t really show true picture of the prices since each statistical bureau measures them little bit differently despite they should follow same standards, it will be always only very rough comparison

it's like saying US has lowest income taxes compared to EU coutnries, but it won't tell you the whole picture what is paid from all those taxes you contribute in Europe, so in the end if you take into consideration all the things you will get for money you pay it can be very different if you have to pay everything extra with low taxes vs high taxes but many things included for free