OSLO, Feb 16 (Reuters) – Aluminium producer Norsk Hydro reported fourth-quarter core earnings below forecasts on Friday blaming one-off costs related to the acquisition of aluminium products firm Sapa, but its key unit’s figures met or were above forecasts. The Norwegian firm’s fourth-quarter core underlying earnings before interest and taxes rose to 3.56 billion Norwegian crowns ($459.91 million) from 1.83 billion crowns a year earlier, but missed expectations of 3.79 billion crowns based on a Reuters poll of analysts. “I am pleased with the strong, full-year and quarterly results, supported by higher aluminium and alumina prices,” CEO Svein Richard Brandtzaeg said in a statement. The company, which reiterated that it expected global aluminium demand to rise 4-5 percent in 2018, raised its 2017 dividend to 1.75 crowns per share from 1.25 crowns per share for 2016.