It varies, and that is before we get to the oddities like the hateful eight and throwback films where people do things, or change during the film to signify a different era. You might also notice trends between regions -- a lot of UK, Australian, some European and BBC productions are noted for using some different approaches (often 1.56:1 or 14:9) to US based films (1.85:1 or 2.35:1, among others).
CinemaScope was once a term people used but as far as practical numbers it is more of a range of them these days. We also have the 4k debate to unpack -- there is/was some disagreement between film videographers and PC makers where the PC types stuck together a bunch of 16:9 monitors and film makers did another thing.
If you really care then IMDB will usually list the aspect ratios under the "Technical Specs" section. Pick a bunch of popular films of the last year(s) (Oscars might be a start
https://www.imdb.com/search/title/?...picture_winners&sort=year,desc&ref_=nv_ch_osc ) and see what goes.