Top casual apparel chain Uniqlo on Tuesday posted a 28.5 per cent slump in January same-store sales - its 16th straight month of sliding sales at outlets in Japan open at least a year. The Tokyo-based parent of the 447-store chain, Fast Retailing Co Ltd, said that slide was slightly less than December when like-for-like sales plunged 30 per cent but was worse than November's slide of 20 per cent.