In pointing out plot holes and the necessity of suspending disbelief, Indy's ability to ride the German Sub is always the most mentioned observation. Marion out drinking a rather corpulent patron always struck me as an interesting super power, and inspired my own superhero who instead of fighting, drinks his villains into submission. Maybe Barry Nugent can help me bring him to life!
Nonetheless there are a couple of textual sources for the definitive answer, shy of trying to count the glasses on the table.
Hopefully the blu-ray release will make that task easier but in print the most notable is the January 1982 issue of Mad Magazine.
I can hear the collective groans of disappointed disbelievers, "is he serious?!?!?
Yet Dick DeBartolo and Frank Jacobs got it right. To ease your pain it's also on page 27 of the Raiders Illustrated Screenplay. The text reads in part; Marion Ravenwood,25 years old, beautiful, if a bit hard looking. At this moment, she can use any hardness in her as she picks up her fourteenth shot glass and tosses it back.
Wow, I don't know how many listeners out there have any idea of the dangers involved with that style of drinking but let's just say it's probably as dangerous as climbing into a refrigerator, nuclear explosion or not.