I'm trying to mimic a certain animation but it's not quite right

I'm trying to create this Radial Counter  and here is the result:

As you can see something is off about it. The circle doesn't follow the rectangles precisely as in the example above. I'm not using any kind of effects or expressions. All I did was adding keyframes, copy- pasting them and eyeballing to try to get it right.  

Any tips on how to make it better?