I feel there is more emphasis on the technique of how to create the graph to promote the subscription-based website's tutorials instead of the actual thing - which IMHO would actually benefit from less programming wizardry. I find the movement distracting. Instead, show the four years side by side. Dingleberry mentions a box plot, but I think the main point would be to just see the development without having to press buttons and watch an animation (and may I suggest a violin plot, kind of like a box plot but it also shows density information). It took me several iterations of switching until I saw details that would be visible right away if all were shown in one graph, for example that how many outliers there are in each profession changes, meaning the development isn't equal but actually reverses in some of them. But you have to keep going back and forth to see which are which.

So this is what happens when your focus is teaching fancy visualization techniques instead of making the point.