Here's why:
* No central database: There's no global organization tracking every single performance of every play, especially for a work as popular and widely performed as Hamlet.
* Amateur productions: Amateur theatre groups, schools, and community organizations perform Hamlet frequently, and these productions aren't always formally recorded.
* Different interpretations: "Hamlet" might be performed in a variety of settings and styles, from traditional stage productions to film adaptations, musical interpretations, and even radio plays. All of these would be considered performances.
However, it's safe to say Hamlet is one of the most performed plays in history, with countless productions happening every year around the globe.