The Wikipedia "List of One Piece Episodes" isn't just a reference tool; it is a living document. It tracks the evolution of the anime industry, the patience of the editors, and the passage of time for a generation of fans.
For the early seasons, the gap is years. (For example, the episode "I'm Luffy! The Man Who Will Become the Pirate King!" aired in Japan in 1999, but didn't hit US screens via the 4Kids dub until 2004). one piece wikipedia episodes