The February sales numbers are in for U.S. retailers, and the results are decidedly...mixed. Only a few dozen retailers still report monthly sales, and those that reported were all over the map in last month. Gap’s (NYSE: GPS) same-store sales increased 3% from last February and Costco’s (NASDAQ: COST) same-store sales were up 6%. Lesser known retailers such as Ross Stores (NASDAQ: ROST), Buckle (NYSE: BKE) and Zumiez (NASDAQ: ZUMZ) didn’t fare so well last month, with each of their same-store sales declining. All of those small-cap stocks plummeted today on the bad sales news. Gap shares, meanwhile, shot up 4.5%. Costco shares, strangely, fell a few ticks despite same-store sales that were not only 6% higher than a year ago, but also outpaced analyst expectations. Limited Brands (NYSE: LTD) , owner of Victoria’s Secret and Bath & Body Works, saw its shares fall half a percent despite a 3% increase in same-store sales. Most of the larger retailers, such as Wal-Mart (NYSE: WMT), Target (NYSE: TGT) and Macy’s (NYSE: M) , no longer report monthly sales. Among those that still do, same-store sales collectively rose 3.8% in February – not bad, but about half last February’s year-to-year sales increase of 7.4%.