What evidence is there that smuggling of alcohol into the United States was large in scale?

At midnight on January 16, 1920, the manufacturing, sale and distribution of alcoholic beverages became illegal in the United States. The relatively quick and easy ratification of the 18th Amendment came as no surprise to its supporters, especially given more than half the states already prohibited alcohol within their borders. The surprise was that Prohibition proved nearly impossible to enforce, quickly becoming one of the most openly violated laws in American history.

corrupt also means cruel