Tolong jelaskan mengenai Piala KNVB: 20 dari AFC Ajax

1916–17, 1942–43, 1960–61, 1966–67, 1969–70, 1970–71, 1971–72, 1978–79, 1982–83, 1985–86, 1986–87, 1992–93, 1997–98, 1998–99, 2001–02, 2005–06, 2006–07, 2009–10, 2018–19, 2020-21