Against tough com­pe­ti­tion from oth­er sand­wich­es and flat to declin­ing restau­rant traf­fic, burg­ers ordered at U.S. restau­rants and food­ser­vice out­lets had a ban­ner year in 2014, finds food­ser­vice mar­ket research from The NPD Group. There were 9 bil­lion serv­ings of burg­ers ordered at U.S. restau­rants