Popular items on the Taco Bell menu, such as Loco Tacos and Nacho Fries, have helped the Mexican-style fast-food chain surge past Burger King.  Taco Bell is now the number 4 restaurant chain in the United States, industry statistics show.

The number 3 chain Subway is currently experiencing slower sales. Therefore, Taco Bell could very well jump into the top three chains in 2018, according to Technomic, a food-service research firm.  “The gap between Subway and Taco Bell is narrowing,” Erik Thoresen, Technomic principal of restaurant research, said. “If Subway’s sales continue to decline, Taco Bell could leapfrog it this year.”

Taco Bell’s U.S. revenues in 2017 grew 5 percent, to $9.8 billion, while Burger King finished the year with U.S. sales of $9.3 billion.  This marked the second straight year Americans favored Mexican fast food over the home of the Whopper.

Subway, which closed 800 locations in 2016 and 1,000 in 2017, saw 2017 revenues decline 4 percent, to $10.8 million, according to Technomic.  The average Subway store pulls in $350,000 in annual sales compared with Taco Bell’s $1.5 million per store, according to John Gordon of Pacific Management Consulting Group.

The rising popularity of Mexican-style cuisine may also be a factor in Taco Bell’s success. The misfortunes of Chipotle Mexican Grill may have helped Taco Bell, too.  “Taco Bell has been growing fast and that could be, in part, because Chipotle stumbled,” said restaurant analyst Roger Lipton.