Q: In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.
Context: The family moved to Holyhead in 1918 because of his father's work in the Merchant Navy. Link Information: none Answer: none
A:
What was the population of Holyhead the year that R. S. Thomas moved there?