I can’t confidently give percentages, but Yale felt like quite a liberal campus–at least relative to the wider US population. My friends tended to be liberal, but I definitely interacted with people from the entire political spectrum at Yale. The Black Lives Matter movement was enormous at Yale, but we also had vocal republicans. One thing I would emphasize is that Yale is overwhelmingly affluent relative to the population. Because Yale has such a large endowment it can offer generous, need-blind, financial aid. Consequently, there will always be a solid mix of socio-economic backgrounds (especially relative to schools like Bowdoin or NYU). Since the soft cut-off for financial aid is a yearly income of $200,000, and 51% of students receive some kind of aid, one can infer that about half of families at Yale earn over $200,000. Personally, I think that this informed campus culture just as much as discrete political preferences did.

I’m a current international student at Yale College. This is a difficult question and different people will have different perspectives. In terms of US domestic politics, the campus is heavily Democrat. However, there are conservative and Republican groups (W.F. Buckley program, Yale Republicans, New Yale Republicans etc.) on campus which offer strong support to their members. Campus debates and dialogues are highly liberal and some conservatives have felt that their views are unwelcome.
I believe one can be detached from national politics most of the time (though election year is an exception). However, Yale remains a politically-charged campus. Actions and statements on campus are often taken and misrepresented by media for their own purposes, and Yale as a whole serves as a supposed symbol for “privileged youth/millenials”. This does cause considerable stress and tension on campus at times.
Overall, however, I believe Yale’s community is more characterised by the way that students care, and are expected to care, for each other especially in tragedy than by the political views that divide them.