What is a question about this article? If the question is unanswerable, say "unanswerable".

In 1976 the future Labour prime minister James Callaghan launched what became known as the 'great debate' on the education system. He went on to list the areas he felt needed closest scrutiny: the case for a core curriculum, the validity and use of informal teaching methods, the role of school inspection and the future of the examination system. Comprehensive school remains the most common type of state secondary school in England, and the only type in Wales. They account for around 90% of pupils, or 64% if one does not count schools with low-level selection. This figure varies by region.

What is the only kind of school operating in England?
unanswerable