I guess the percentage that they shown is quite low because I don't think that those researchers got the numbers of pirated games. In Thailand, you can find a shopping mall full of pirated softwares and games.
According to the research, the 30% are those who downloaded free demos, and game freebies on the Internet. People who are planting digital plants and fishing digital fishes on social network also falls into that 30% category.
Anyway... demos and free online games are still acceptable because even though they are free, they are still legal. You must hope that you don't waste too much time on it though, coz those free games are the ones that usually very very addictive.
Beware of these addictive games...