Countries with the most islands (including dependencies), quiz 1–30: United States 40, United Kingdom 36, France 32, Greece 27, Canada 25.5, Indonesia 20.3, Russia 19, Italy 15, Philippines 13, Australia 12, Japan 12, Denmark 11.5, Netherlands 11.5, Spain 11.5, (Antarctica 9), China 9, New Zealand 9, Germany 8.5, Norway 8, Bahamas 7, India 7, Chile 6.5.
For more statistics visit the blog post (not yet released as of typing).