Never forget to analyze the timeline provided in the image. There is always a clue as to whether this is a continuing process / measurement, previously completed task, or past measurement consideration. In this case, where no dates or years are mentioned, it is safe to use the present tense reference seeing as how these could be considered a continuing or ongoing task. This is a slight GRA inaccuracy and a partial C+C misanalysis on the part of the writer. He chose to use the incorrect time reference this time.
There will be LR deductions in addition to increase GRA deductions due to lack of clarity in a sentence. When he wrote:
slowest level of pace
he neglected to double check the meaning of the words level and pace. These are 2 different measurement references that cannot be used together due to the different measurement basis:
level - having no part higher than another; having a flat or even surface.
pace - a rate of activity, progress, growth, performance
Therefore the reference should be "slowest pace" since it refers to the speed of the line graph presentation.
Most of the problems the writer has are in reference to word usage, sentence structure, and how these relate to the clarity of the presentation. He must work on improving these areas next time.