Avoid use of the word "prove" in a discussion of science and scientific theories. Science can't prove theories true, it can only prove theories false. Philosopher David Hume expressed this best: “No amount of observations of white swans can allow the inference that all swans are white, but the observation of a single black swan is sufficient to refute that conclusion.”
It can at best inductively prove it - the scientific approach, or alternately do what you called '100% rate' (the hidden words there being 'so far').