Over the past month, the 500 customers have downloaded the following number of songs from WalMart's website (obviously, they have had more, but we need to use workable numbers): 121 customers downloaded 3 songs, 82 customers downloaded 6 songs, 184 downloaded 8 songs, and the remaining customers downloaded 11 songs. What is the average number of songs downloaded by a customer? (please round your answer to 2 decimal places)