Now let's look at the win-loss percentage between the 7-7 wrestlers and the 8-6 wrestlers the next time they meet, when neither one is on the bubble....

Now let’s look at the win-loss percentage between the 7–7 wrestlers and the 8–6 wrestlers the next time they meet, when neither one is on the bubble. In this case, there is no great pressure on the individual match. So you might expect the wrestlers who won their 7–7 matches in the previous tournament to do about as well as they had in earlier matches against these same opponents—that is, winning roughly 50 percent of the time. You certainly wouldn’t expect them to uphold their 80 percent clip. As it turns out, the data show that the 7–7 wrestlers win only 40 percent of the rematches. Eighty percent in one match and 40 percent in the next? How do you make sense of that?

Which type of evidence does the authors use in this excerpt to support the claim that some sumo wrestlers will intentionally lose a match?