Croatians began casting ballots on Sunday in a presidential run-off, with incumbent Zoran Milanovic ahead in opinion surveys of Dragan Primorac of the ruling Croatia's Democratic Union.Around 3.8 million people are eligible to vote in the second round. In the first round two weeks ago, Milanovic won 49.1% of the vote – narrowly missing an outright victory. Primorac won 19.35%.Opinion polls showed Milanovic of the Social Democratic Party leading with 67.4% against Primorac with less than 27%.The vote comes as Croatia struggles with the highest inflation rate in the Eurozone, endemic corruption and a labor shortage.