The number of Grands Prix held in a season has varied over the years. The inaugural world championship season comprised only seven races, while the season contained twenty-one races. Although throughout the first decades of the world championship there were no more than eleven Grands Prix a season, a large number of non-championship Formula One events also took place. The number of Grands Prix increased to an average of sixteen/seventeen by the late 1970s; simultaneously non-championship events ended in 1983. More Grands Prix began to be held in the 2000s, and recent seasons have seen an average of 19 races. In , and the calendar peaked at twenty-one events, the highest number of world championship races in one season.