Walmart sales, often a bellwether for the rest of the economy, may be in question after an email was published, but Costco was up $547 million, officials say. Last month, a Walmart email asked \"Where have all the customers gone and where\'s their money?\" Business analysts said the stagnant sales might be due to the end of the payroll tax holiday that ended Jan. 1. The federal tax break was designed to boost consumer spending and added about $19 a week to many paychecks during the last two years. While Costco\'s discount peers Target Corp., Sam\'s Club and Walmart Stores logged weaker sales in February, Costco continued to generate consistent, strong growth across all general merchandise categories, The Wall Street Journal reported Tuesday. The company, which caters to people who buy in bulk, operates 622 warehouse stores: 448 in the United States and Puerto Rico, 85 in Canada, 32 in Mexico, 23 in the United Kingdom, 13 in Japan, nine in Taiwan, nine in South Korea and three in Australia. Craig Jelinek, Costco\'s chief executive officer, recently made headlines for endorsing President\'s Barack Obama\'s proposal to raise the minimum wage to $9 an hour. Jelinek, however, went further, urging the U.S. Congress to raise the minimum wage to $10.10 an hour. \"At Costco, we know that paying employees good wages makes good sense for business,\" Jelinek said in a statement last week. \"Instead of minimizing wages, we know it\'s a lot more profitable in the long term to minimize employee turnover and maximize employee productivity, commitment and loyalty.\" Costco is known for paying its workers better wages than its competitors and for providing healthcare for part-time employees. Fortune magazine reported an average Costco worker made about $45,000 in 2011, compared with an average of about $17,486 per year for a worker at comparable Walmart-owned Sam\'s Club, the Huffington Post reported.