Maybe because there are no children in Vatican City to dilute the statistics, its residents take first place by each consuming nearly 100 bottles of wine every year. France is a distant #3.
The U.S. population trails far behind at about 13.5 bottles/year, but there are 70 million children (defined as 0-17 years old) pulling us down in the rankings. Not to mention the 40% of American adults who don't drink any alcohol. The 18-20 year old group may be enjoying wine, but there's no data available.
Surprisingly, Washington, D.C. has the largest per capita wine consumption in the U.S. One would think Congress would get along better, and be more productive, after enjoying 34 bottles of wine/year.