Should have noted that Tobias Buckell was the person with the Excel spreadsheet! His website is www.tobiasbuckell.com--he's got a novel coming out soon.
This panel on Writer's Block concluded pretty firmly that "block" is the outcome, not the process. When you are not producing writing, you are blocked. The interesting part is why. Are you blocked because...
1. You don't want to write
2. You are afraid to write
3. You can't write because you lack some essential skill you have to develop first
4. You can't write because something needs to be resolved in the plot or character first
5. You block yourself because you overcriticize yourself ("it's no good")
6. You block yourself because you compare yourself to the wrong standard ("I'm not writing 5,000 words per day, therefore I'm no good.")
7. You're too anxious to write ("I only have an hour--it better be good!!!")
And so forth. The key point here is that different blocks must be approached in different ways! Fear of writing is something that must be addressed carefully, say by setting a very low goal (like the Ph.D I met who set a minimum goal of one sentence per day on her dissertation). Being blocked because you are subconsciously trying to figure out a plot point--which happens to my mystery writer wife Toni at least once per book--is a different issue which will generally resolve itself. Being blocked because you lack a skill must be addressed either by explicitly building that skill or setting the work aside and doing something else! Anxiety can be addressed by adjusting the goals or sometimes through physical effort--take a walk, work out, do something else relaxing.
So do what you can to identify what is blocking you first, and then approach it. I had heard for years that the brilliant SF writer Theodore Sturgeon had terrible writer's block. Then I realized that they were selling Volume IX (yes, nine of his Collected Works. Writer's block is a relative thing...