LOS ANGELES (Reuters) - "King Kong" reigned at the North American box office for a second weekend on Monday, leading a busy field of Christmas newcomers and expansions even as overall ticket sales fell. Director Peter Jackson's big ape remake sold an estimated $31.4 million worth of tickets in the four days beginning Friday, taking its total to a modest $118.7 million after 12 days. Because of the holiday season, movie industry observers are still not certain how to classify the performance of Universal Pictures' $207 million movie. After a slow start, it picked up steam last weekend, but was surpassed in subsequent days by the weekend's No. 2 movie, "The Chronicles of Narnia: The Lion, the Witch and the Wardrobe." "It is forging its own pattern of performance, but it is doing sizable business every day," said Marc Shmuger, Vice Chairman of the General Electric Co.-controlled studio. [More]