Clothing maker and retailer Jones Apparel Group Inc on Tuesday posted a 34 per cent year-on-year plunge in first-quarter earnings amid disappointing sales dropped and an accounting change. The New York-based company, whose brands include Jones New York and Nine West, said its net income fell to $70.7m, or 53 cents per diluted share, compared with $107.9m, or 84 cents per share, in 2001.