Too easy :) Percentage of internet-enabled PC's with different types of media players. The most common one is Adobe Flash player. (Via google search)

Or maybe I misunderstood the question.

@%#+ Rajarshi was faster ;-) And right, too easy ... the y-axis text returns the exact graphic as first Google hit.

I thiought it was the standard chemoinformatics paper. The left hand side is the method of the aithors - the other methods are the competitors - by definition - worse. Th actual annotations don't matter since all units are in arbitraries.