And in other news, 100% of music in America is pirated (iTunes was shutdown years ago), the sky is only blue at night (black during the day), MyCE finally launched nuke-bombs against Russia, and, most important of all... the FSF is secretly turning our computers into Transformers, designed to enslave the human race.
All sarcasm aside, I seriously doubt that only 10% of ebooks have been paid for. I'll bet the Dutch anti-piracy lobbyists paid GfK to "adjust" these results, in order to scare the government into strengthening copyright laws. Odds are, these are the same jerks (to put it kindly) trying to push the Trans Pacific Partnership (aka, the Toilet Paper Protocol, or TPP) onto the masses. After all, you have to admit... the timing is pretty convenient.