Sales of desk and laptop computers declined last year, extending a slide started in 2012, according to figures released on Wednesday by two market trackers. Preliminary figures from Gartner indicated that PC shipments last year tallied 269.7 million units in a 6.2 percent decline from the previous year. Internation Data Corporation pegged the number of machines shipped last year at 260 million, calculating a 5.7 percent drop from the previous year.