CeSID is now estimating that turnout was 50% one hour before the official poll closing time. If the competing figures follow the pattern set so far, RIK's numbers will be higher. For the referendum to pass, a majority of registered voters must have voted yes, which means that the overwhelming majority of votes will have to be in favor.
Image: Turnout at 7 PM, according to CeSID.
Update: B92 is reporting (only by audio now, no text to link) that CeSID's estimate is that the referendum has succeeded, based an analysis of a random sample of polling places.