Passage: The Spa-Francorchamps motor-racing circuit hosts the Formula One World Championship Belgian Grand Prix. The Belgian driver, Jacky Ickx, won eight Grands Prix and six 24 Hours of Le Mans and finished twice as runner-up in the Formula One World Championship. Belgium also has a strong reputation in, motocross with the rider Stefan Everts. Sporting events annually held in Belgium include the Memorial Van Damme athletics competition, the Belgian Grand Prix Formula One, and a number of classic cycle races such as the Tour of Flanders and Liège–Bastogne–Liège. The 1920 Summer Olympics were held in Antwerp. The 1977 European Basketball Championship was held in Liège and Ostend.

Question: How often do these events occur?
annually