For a while now, I have been wondering what the red guardian bonus to tribute means. It says +X% to tribute, where X is a number from one to six, depending on the guild. I see (at least) two possible meanings for this:

Multiply tribute chances by 1.0X, so if X is 6, so a level 10 3 star kingdom would have a 21.2% chance of occurring.

Add X to the tribute chance, so a level 10 3 star kingdom would have a 26% chance of occurring.
To test this, for the last few weeks I have been collecting statistics on all my tributes. With 29 three star and three nine star kingdoms, I had 405 kingdoms in 49 tributes 8.266 average; with four nine stars, I had 1519 in 186 = 8.16 average. Unfortunately, the last figure is between my two hypotheses. The first is almost ruled out (over five standard deviations too low), while the second is looking shaky (three standard deviations toohigh). To conclusively rule out both requires many thousands, not many hundreds of tributes. So it would be nice if people would post their tribute statistics, if they have them. Please include how many three and nine star kingdoms (and less than three stars), how many kingdoms gave tribute, and how many tribute attempts you did. Thank you.