This is not new, but it’s an interesting article on one aspect of this topic. In recent years the balance has shifted more towards graduate students at Stanford in terms of numbers, as graduate student numbers have gone up and undergraduate numbers have been pretty stable - as of now about 43% undergrads compared to ~ 50% 30 years ago. Still more balanced than some schools, e.g. IIRC Harvard is about 30% undergrads.
https://alumni.stanford.edu/get/page/magazine/article/?article_id=63084