Hamlet
For how many years had te gravediger been digging graves?
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The gravedigger who is thirty, has been digging graves for sixteen years.
The gravedigger tells Hamlet that he has been digging graves since the day Old King Hamlet defeated Old King Fortinbras, the very birthday of Prince Hamlet — "he that's mad, and sent to England" — thirty years ago.
http://www.cliffsnotes.com/study_guide/literature/hamlet/summary-analysis/act-v/scene-1.html