How many of Michael Phelps' twenty-three Olympic gold medals were won as part of the US relay team?

Michael Fred Phelps II (born June 30, 1985) is an American former competitive swimmer. He is the most successful and most decorated Olympian of all time with a total of 28 medals. Phelps also holds the all-time records for Olympic gold medals (23), Olympic gold medals in individual events (13), and Olympic medals in individual events (16). When Phelps won eight gold medals at the 2008 Beijing Games, he broke fellow American swimmer Mark Spitz's 1972 record of seven first-place finishes at any single Olympic Games.

On August 13, 2016, at the Rio Olympics, in the 4 × 100-meter medley relay, Phelps ended his career with another gold medal, his 23rd at the Olympics and his 28th Olympic medal overall. Together with Ryan Murphy, Cody Miller, and Nathan Adrian, swimming as the butterfly leg of the medley, they broke the Olympic record, and won the United States' 1001st all time Olympic gold medal, in accordance with the United States Olympic & Paralympic Committee. This was Phelps tenth Olympic gold medal with a US relay team. Phelps retired from competitive swimming following the Rio Olympics.