In the Bicycle Motocross context, sanctioning bodies are chiefly responsible for providing insurance coverage and other "back office" services to local tracks. They also keep points on riders' performance throughout the year, and undertake the production of a national racing series (which is typically 18-22 weekends per year). Riders are permitted to race at the sanctioning body's affiliated tracks and national events via the purchase of an annual membership which costs (in the US) US$60. As part of their administrative "service provider" role, BMX sanctioning bodies also determine the rules of competition, such as clothing requirements, age and gender divisions (or "classes"), as well as the rules and protocol for advancement in proficiency classes (Novice, Intermediate, Expert, A Pro, AA Pro, Women, and Vet Pro in ABA, In NBL Rookie, Novice, Expert, Super-Ex, Elite, Masters are the proficiencys).