MS Excel is a beautiful thing. My point is that When you're crap animations are made in five minutes and when you're pretty good you can make animations in five minutes but in between it takes time and after that they're so good that they take ages.
That chart doesn't prove anything.
There is always the length factor of the animation, so it could take longer in general. Plus, when you're good, you can do things quicker :/ It doesn't take me an hour to make amazing scenery anymore. I can do it in 5 minutes.
Yes, the chart proves nothing. I just thought it would be a nice way of making my point. Generally the best animators tend to make (or at least only publish) the stuff that's taken them longer.