It's 11:00 p.m. Do you know where your 21- to 34-year-old is? They are probably in a bar! According to an advertisement for "I Am TV" - I have no clue what that means either - in the current Advertising Age, 75 percent of bar-goers are 21 to 34 years old. They average two evenings per week at their favorite bar. They average two and a half hours per visit. All this from an Arbitron study conducted in September. I have a quibble with this study, however. It says bar-goers average two evenings per week at their favorite bar. Most bar-goers I know go out around two evenings per week, but not to the same place. And since the Arbitron study does not conform to my anecdotal impressions, it must be flawed, right? Either that, or there's a lot more drinking taking place across America than I had previously thought.