For a typical skilled reader, up to about 25-30%. For people with reading challenges (dyslexia, ADHD, vision impairments), it could be much greater. One fellow with ADHD (and two PhDs) said that he could read about 3x the speed with BeeLine versus regular text.
To get a sense of what the speed difference could be for you, check out our "Reading Challenge". [1] It's not super scientific (you might have more knowledge of one of the topics already, which would bias your results), but it can give you a ballpark figure.
Thanks for pointing out the issue with the research summary link. I'll get that fixed ASAP! There's actually newer research that shows even larger gains for students with reading challenges, as well as data from companies (including a YC company) who saw dramatically lower churn rates and/or higher engagement for users reading with BeeLine in their apps.