A new shoppers' survey ranks San Antonio-based HEB as the nation's top grocery retailer. The third annual Retailer Preference Index from Dunnhumby, a global customer data science company, surveyed seven-thousand U.S. households concerning the 60 biggest grocery outlets. HEB took the top spot, occupied for the past two years by Trader Joe's. HEB also leapfrogged Amazon and Costco. It's quite an accomplishment, since HEB has no stores anywhere in the U.S. outside of Texas.