Eleven convenience-store retail chains landed on the Forbes 2013 list of America's largest private companies. Overall, 224 companies made the list, up from 220 last year. The companies have combined revenues of $1.61 trillion, an 8% increase over the previous year, according to the magazine. Two convenience industry chains, Pilot Flying J and Love's Travel Stops & Country Stores made the top 10, coming in at No. 7 and No. 9, respectively.