You could cobble it together pretty easily but off the top of my head I think Bradley played every minute and Pulisic played close to every minute (he was subbed off in garbage time vs Panama and in the last few minutes @Mexico IIRC). Probably a pretty steep drop off from there, my guess is Howard would be third.
Finding anything on the USSF site is a nightmare. I've definitely found WCQ minutes and stats somewhere, but that is more than just the Hex. Wikipedia might have it. MLsoccer.com might have it.
Wikipedia usually has lineups and sub info right there on the page and worst case would have links to game reports on the CONCACAF or FIFA website, you could tally it up pretty easily from there using Excel
Here you go (this ignores injury time): Bradley 900 Pulisic 843 Gonzalez 720 (didn't play at all at home vs T&T or CR, played every minute of every other game) Altidore 697 Nagbe 599 Howard 580 Wood 552 Villafana 497 Besler 441 Dempsey 421 Yedlin 376 Brooks 340 Johnson 331 Guzan 320 Ream 290 Zusi 283 Acosta 243 Arriola 238 Jones 236 Chandler 164 Beasley 151 Bedoya 122 Morris 95 McCarty 34 Gooch 20 Kljestan 18 Lletget 18 Orozco 9 Feilhaber 7
https://www.ussoccer.com/~/media/files/media-guides/2018mntmgfinal.pdf is a Media Guide with all the lineups in USMNT history. It states the subs and who they replaced, but not what minute.