By my own research and classification, "general news" sites accounted for 4.1% of front-page stories on HN in 2022 (most recent complete year's data), and that percentage has
fallen over the years (it was 8% in 2009), with a corresponding
rise in programming-specific sites (GitHub/GitLab, and language-specific sites, e.g., "python.org" or "golang.org".)
Sites classified as "general news" (ordered by frequency in the front-page archive): nytimes.com, bbc.com, bbc.co.uk, theguardian.com, washingtonpost.com, reuters.com, npr.org, cnn.com, slate.com, vice.com, latimes.com, cnet.com, yahoo.com, sfgate.com, cbc.ca, cnbc.com, guardian.co.uk, bits.blogs.nytimes.com, vox.com, salon.com, time.com, nymag.com, telegraph.co.uk, boston.com, newsweek.com, chronicle.com, msn.com, axios.com, news.com.com, propublica.org, independent.co.uk, timesonline.co.uk, mercurynews.com, theglobeandmail.com, pbs.org, theintercept.com, usatoday.com, buzzfeednews.com, spiegel.de, rollingstone.com, thestandard.com, go.com, smh.com.au, cbsnews.com, abc.net.au, nbcnews.com, seattletimes.com, aljazeera.com, bloombergview.com, motherjones.com, firstlook.org, thehill.com, apnews.com, informationweek.com, news.com, thedailybeast.com, huffingtonpost.com, theage.com.au, csmonitor.com, nwsource.com, japantimes.co.jp, thestar.com, bostonglobe.com, dw.com, indiatimes.com, nypost.com, ap.org, chicagotribune.com, sfchronicle.com, dailymail.co.uk, news.com.au, foxnews.com, kqed.org, theatlanticwire.com, scmp.com, texasmonthly.com, wbur.org, yahoo.net, swissinfo.ch, nationalpost.com, spectator.co.uk, sfweekly.com, detroitnews.com, theweek.com, nzherald.co.nz, washingtonexaminer.com, aljazeera.net, cbslocal.com, nltimes.nl, weeklystandard.com, ctvnews.ca, miamiherald.com, nydailynews.com, thetimes.co.uk, dallasnews.com, startribune.com, bostonherald.com, euronews.com, kuow.org, themorningnews.org, upi.com, globalnews.ca, guardiannews.com, theherald.com.au, thesun.co.uk, belfasttelegraph.co.uk, houstonchronicle.com, ibtimes.co.uk, koreaherald.com, metro.co.uk, mirror.co.uk, seattleweekly.com, standard.co.uk, dailyherald.com, huffingtonpost.co.uk, huffingtonpost.com.au, huffpost.com, inquirer.com, ktvu.com, ocweekly.com, sundayherald.com, theweek.co.uk, wpri.com, wtsp.com, americanchronicle.com, annarborchronicle.com, augustachronicle.com, catholicherald.co.uk, dukechronicle.com, heraldsun.com.au, katu.com, kdvr.com, kfor.com, ktla.com, myfox8.com, myfoxdc.com, myfoxny.com, news-herald.com, news.google.ca, pressherald.com, thechronicleherald.ca, timesherald.com, wttw.com, wtvr.com, wunc.org, wvgazette.com.
This is based on downloading all archived HN front pages from 2007-02-20 through 2023-06-21 and analysing stories by title, site, votes, comments, and submitter.