Seventeen is also:

• The most frequent number that people select between 1 and 20.
  
• The number of times that forty-two appears in the Hitchhiker's Guide to the Galaxy series.
  
• The average number of square feet of skin of a teenage girl. (I don't want to know how this was discovered.)
  
• The average number of seconds that an adolescent male goes between sex-related thoughts. (Scientifically proven.)