Nissan Motor Co saw the first decline since 1998 in its operating profit, during the April-September period, because of slow sales, DPA QUOTED the company's sources as saying Thursday. Operating profit for Japan's second-largest automaker fell 15.3 per cent to 348.6 billion yen (3.02 billion dollars) in the first half of the business year ending in March 2007. The operating profit measures earnings before interest payments and income taxes. Nissan saw a 1-per-cent rise in its sales to 4.53 trillion yen, while its net profit also jumped 18.8 per cent to 274.18 billion yen from the same period a year before. The increase in net profit was attributed to the sale of Nissan Diesel Motor Co Ltd shares, favourable pension benefits from operations in China and tax benefits resulting from losses incurred from domestic-dealer restructuring, the company said. Sales were down 6.9 per cent from the year before to 1.71 million units globally during the first half of the year.