The two most common things to be found on the back of a sci-fi/fantasy novel (idea)

A note: Once upon a time this was an addendum to a previous writeup, long since vanished.

All works cited below are paperback copies.

For science fiction, based on 10 classic works taken from my bookshelf :

• "Cover printed in USA": 8, for 80 %
• Reviewer endorsements: 6, for 60 %
• Bar Code: 5, for 50 %
• Black backgrounds: 5, for 50 %
• Author endorsements: 2, for 20 %
• The words "Philip K. Dick": 0 (sorry,moJoe)

For fantasy, based on 6 classic works taken from my bookshelf :

• Reviewer endorsements: 4, for 66.7 %
• "Cover printed in USA": 4, for 66.7 %
• Bar Code: 6, for 100 %
• Black backgrounds: 2 for 33.3%
• Use of the color red: 4 for 66.7%
• Endorsement by Piers Anthony: 1, for 16.7 %