HENDERSON, TN — The burgeoning effort to unionize pizza delivery drivers across the country has stalled. Dirvers at a Sunbury, Ohio restaurant voted 9-to-3 against establishing the first pizza delivery drivers union shop in the country, according to a recent Associated Press report.The Association of Pizza Delivery Drivers, based in Hendersonville, Tenn., failed in November to organize a local in Lincoln, Neb. A vote at a Domino´s franchise there ended in a tie.Union organizers wanted higher wages and to get a mileage reimbursement rate to replace the flat rate per delivery. Drivers at the Sunbury store earn about $6 an hour and 75 cents per delivery. The drivers are not reimbursed for mileage and are not scheduled for pay raises. There are an estimated 350,000 pizza drivers in the U.S., the AP report said.