Facts aren't usually copyrightable and I doubt
database rights apply
(I don't know much about them, though), so it's just the presentation
of the data in a chart that could potentially be protected. If you
take the numbers and produce your own chart you'll be absolutely fine.
I'm not sure there is enough creativity or work involved in making the
charts for them to be copyrightable anyway.
That said, the easiest solution is probably just to ask the creator to
release them under CC-BY-SA here:
http://en.wikipedia.org/wiki/User_talk:Henrik
They might not be, but with that San Francisco bus data issue [1]
happening at the moment, everyone's checking everything these days to
cover their asses.
[1]. The Battle Over Who Owns Bus Arrival Times: