<P> "99 Bottles of Beer" is an anonymous folk song dating to the mid-20th century . It is a traditional reverse counting song in both the United States and Canada . It is popular to sing on long trips, as it has a very repetitive format which is easy to memorize and can take a long time to sing . In particular, the song is often sung by children on long bus trips, such as class field trips, or on Scout and / or Girl Guide outings . </P> <P> The song's lyrics are as follows: </P>

Who wrote 99 bottles of beer on the wall