Indiana Jones’ adventures began with Raiders of the Lost Ark which was set in 1936.
The most recent film, Indiana Jones and the Kingdom of the Crystal Skull was set in 1957.
It’s been 13 years since that movie came out, it will be 14-years-old when Indiana Jones 5 is released.
And so it stands to reason that since actor Harrison Ford will be over a decade older, the new movie will take place more than a decade after the last one.