Japan's leading casualwear retailer, Fast Retailing Co Ltd, has posted a record 44.2 per cent plunge in May same-store sales at its Uniqlo chain - its eighth consecutive fall in monthly sales. The results saw its share price fall around 10 per cent on Tuesday. Its previous record fall in monthly same-store sales was in April when they plunged 42.9 per cent compared to the year-ago period.