I’m believe that’s the wrong way to look at it. Those dots are the result of a Monte Carlo simulation. I think at this point, the actual probability distribution is even, along the entire line. No spot along it is likelier than any other. The full line currently extends many times the diameter of the Earth out in both directions. Probably one direction is shorter than the other. They might be able to assign higher probabilities to different places at some point, but that will happen only after the chance of hitting Earth becomes a definite 100%. Based on what I learned when I asked a similar question a while ago, we might never get that level of certainty before it either hits or passes on by.