Premise: "Boat on the River" is a 1979 song by Styx, from their album "Cornerstone". It was released as a single in 1980, but did not chart in the band's native United States. However, it was popular in several German-speaking countries, becoming a top-five hit on the German, Austrian and Swiss charts (reaching number one on the latter.)
Hypothesis: Boat on the River sold billions of records.