The trends are remarkably constant from 2013 throughout the whole of 2014. So this is established performance, it doesn't change from one week to the next, and it is the base on which future results will be founded. This is the only proper analysis of peak-time speeds I know of.
If you have specific guesses about any changes for ISPs in 2015, then nothing stopping you saying them
When fresher results come we can see if you were right.
If people know so well how things are right now, what they were half a year ago should be dead easy! Yet no takers so far!
(G.INP is irrelevant and there is no evidence whatsoever of a general BTw issue to affect all 3 BTw ISPs, but more to the point you sure can't see 3 equal looking-graphs anyway!)