I'm not sure first year students always have selected a major, but if we go by degree at graduation, I think this article (and the charts therein) is useful: https://www.chartr.co/newsletters/2023-10-08

(n.b. No archive.org evergreen link available, alas)

> " 20 years ago, roughly 8% of all US bachelor degrees were attained in the 4 core humanities subjects — a figure that’s fallen every year since 2007, with the share now sitting at just 4% per data from the National Center for Education Statistics. Conversely, STEM subjects (science, technology, engineering and math) have been growing at an unparalleled pace, as students swap Charles Dickens for computational dynamics and Jane Austen forJavascript."

> "Indeed, computer science has risen from a 2.7% share of all degrees in 2009 to 5.4% by the end of 2022, while engineering has risen from 7.2% to 9.4% in the same time frame — more than double the share that the core humanities subjects currently occupy."