These "world statistics" are questionable at best. The statistics rest on fragile human honesty
The percentages are higher than those supplied worldwide, and are more or less in tune with each other.
Hiding ones sins and "allergy to disclosure" of something of grave implication or consequence like having cheated on one's spouse is not something most ppl would freely fess up on, especially in many cultures and with the typical take of religion, which ultimately not only skews the data in immigrant-rich countries btw, but drastically misrepresents the data of a wide sweep of origin countries.
Not to mention, in the end you're dealing not with a nation, but a person. The individual cheating odds of any given person being pretty much 50/50.