More than half of U.S. revenue for Wal-Mart Stores Inc. now comes from grocery sales.

In its annual report filed with the Securities and Exchange Commission, Wal-Mart said groceries generated 51 percent of its U.S. sales in fiscal year ended Jan. 31, up from 49 percent a year ago.

Wal-Mart’s grocery category is the largest of the company’s six merchandise units, including meat products, produce, household chemicals and pet supplies. Wal-Mart has been aggressively converting existing stores into supercenters, 100,000 square-foot stores that sell consumables in addition to clothing, electronic products and household furnishings. Last year Wal-Mart converted 86 existing locations into supercenters and opened 49 new supercenters.

The retailer now operates 2,750 supercenters in the U.S., while paring back its traditional discount stores to 803 from 1,350 five years ago.

Despite Wal-Mart’s move into the grocery category, most Americans continue to buy their meat from supermarkets. According to a recent Power of Meat survey by the Food Marketing Institute and the American Meat Institute, 68 percent of consumers still buy meat primarily at supermarkets, while only 19 percent do so at supercenters.