The slowing economy didn't keep holiday shoppers from opening their waThe slowing economy didn't keep holiday shoppers from opening their wallets This Black Friday. Early returns show retailers posting more than ten and a half billion dollars in sales. That's three percent higher than last year. The optimistic numbers come from shopper-trak RCT, a Chicago-based research firm that tracks sales at more than fifty-thousand stores. Still, retailers are cautious. Black Friday was their biggest sales-day of the holiday season last year. And this year, shoppers indicated that they may be *finishing* their shopping rather than *begining* it.