The low scores are the reason why football is so exciting. Both teams know a single goal could change the course of the game. In American sports when it is 52-11 who cares if the losing team scores?
(One more tip for the Amercian Football fan: multiplying every score by 7 is a good way to convert to something more familiar, kind of like converting Celcius to Fahrenheit.)
In 2006, the average world cup combined score was 2.3 goals: http://www.insidescience.org/current_affairs/best_team_not_g...
In 2006, the average NFL combined score was 20.7 points: http://wiki.answers.com/Q/What_is_the_average_score_for_one_...
20.7/2.3 = 9