Your facts are not accurate. Normally a bottle of 0.75 liters is consumed by 3 people. It, apparently, does not get them drunk and the same exercise is repeated at least twice. I have not seen people in the US drinking vodka in shots. For some strange reason Americans drink vodka with ice, as a long drink. Here, in Russia, vodka is drunk in small shots (ryumki) or with regular glasses (stakan) - always at one gulp, of course.