August 2 (SeeNews) - Croatian hotel operator Valamar Riviera [ZSE: RIVP] said its operating revenue rose 114% year-on-year to 266.4 million kuna ($42.2 million/35.5 million euro) in the first half of 2021, as the number of tourist overnights at its accomodation facilities leapt 134% to 851,183.