The first official ball used in volleyball is disputed; some sources say Spalding created the first official ball in 1896, while others claim it was created in 1900. The rules evolved over time: in 1916, in the Philippines, the skill and power of the set and spike had been introduced, and four years later a "three hits" rule and a rule against hitting from the back row were established. In 1917, the game was changed from requiring 21 points to win to a smaller 15 points to win. In 1919, about 16,000 volleyballs were distributed by the American Expeditionary Forces to their troops and allies, which sparked the growth of volleyball in new countries.