Washington-based Costco Wholesale Corp saw net sales increase 12% during the five weeks ended 7 April 2002, year on year. The sales reached US$3.46bn, compared to US$3.08bn in the same five-week period of the prior fiscal year. For the first 31 weeks of its fiscal 2002, ended 7 April, Costco also reported a 12% rise in net sales, to US$22.36bn from US$19.98bn during the comparable period of the prior fiscal year.