Depends on whether it's statistically significant because it's never going to be flat. And of course it's of no use going forward and just gives context to previous results. Even if it is statistically significant it won't persist because so many people see it.
The chart actually tells many stories that need to be thought about and investigated. A downward slope could just as easily mean there's simply been a run of results with winners averaging under 6
But it's akin to how a swing trader would look at the market tendency to have steamed or drifted. If it's been steamy, and they have a tendency to back first then they've had a tail wind and probably flattering results. Interpreting this sort of thing is where art meets the science and you only develop the 'feel' for the implications after a few years.
I just thought it was something you might want to add to your 'state of the markets' reporting to flesh out the bigger picture rather than it being something you had the experience to make much use of now.
