*Apple sold 78.3 million smartphones worldwide in the December-ending quarter, IDC says. Samsung sold 77.5 million.
*IDC preliminary data shows smartphone vendors together shipped a total of 428.5 million units during the fourth quarter of 2016.
*For full-year 2016, a total of 1.47 billion smartphones shipped around the world, even as fears continue that the market is shrinking.
*Full year 2016 sales marked the highest year of shipments on record, IDC says, but that was just a 2.3% increase from the 1.44 billion units shipped in 2015.