Henrik Berggren, CEO and co-founder of e-Reader start-up Readmill, divulged the information at the Media Evolution conference in Sweden on Wednesday.
His comments were first reported by VentureBeat.
Readmill also found that people spend more time reading per book on their phones, more often open eBooks on their phone and are also more social on which books they are reading.
The Germany-based firm offers a mobile eReader app (free, iTunes) for books on iOS and claims that it offers a better reading experience than Apple’s own iBooks. The app supports both ePub and PDF formats.