Premise: The 1976 SCCA/USAC Formula 5000 Championship was the tenth running of the Sports Car Club of America's premier open wheel racing series and the third to be co-sanctioned by the Sports Car Club of America (SCCA) and the United States Auto Club (USAC).
Hypothesis: The Sports Car Club of America's premier open wheel racing series had already run ten times prior to the 1976 SCCA/USAC Formula 5000 Championship.