Good quesion @newtechblog.
Green means that the value has increased as compared to 1-week, 4-weeks, 12-weeks or 1-year.
If we take Amicable Numbers, the GRC per 1k RAC has increased by 1.1% since last week but has lost 5.5% since 4 weeks.
I hope this answers your question.
ok...it is understood