Warehouse retailer Costco ( COST ) said comparable-store sales in October fell 1%, while total sales for the month increased 2% to $5.3 billion from $5.2 billion a year earlier. Analysts surveyed by Thomson Reuters expected comparable-store sales to increase 3.6%. U.S. comparable-store sales rose 2% and international comparable-store sales declined 10%, Costco said in a press release Thursday. Excluding the negative effect of foreign exchange, international comparable-store sales in October rose 9% in local currency, while total company comparable-store sales would have increased by 3%, Costco said. Changes in gasoline prices didn't have a material impact on sales, the company said.