is each change in direction a year?
no
I thought each was a point was a year as well. If this is not the case, please explain it. It looks to me like there are 5 data points for the purple (Frank), 9 for the Black (Self), 9 for the blue (Weber), and 4 for the red (unknown). Also, I went back and looked at the coaching changes 4 years ago and I can't figure out who the red would be unless a datapoint is missing.