Does this mean that it was the lowest price in the last eleven years?

Question

Does this mean that it was the lowest price in eleven years or is it an idiom?

But then the oil price dropped, and by early 2016 it had slumped to an eleven-year low.

Answer 1

This clearly means that the price had dropped in 2016 and it became as low as it was eleven years back. Here, in 2005. This is no idiom.