Use this as a reference to understand what each of the ranks used in the homunculus progress pages.

Making Sence of the Ranks
AbysmalAbysmal is the lowest rank a stat can have. Statistically, only 5% of the homunculus created will rank this low.
TerribleThe second lowest rank. Only the bottom 10% of homunculus will be Terrible or Abysmal.
PoorPoor rank represents the low end of the spectrum. 20% of homunculus will be Poor or lower rank.
Below AverageHaving a stat below average sucks, but its not that far from average. 40% will be this rank or lower.
AverageThis rank is right on the average homunculus stat gain. 60% of homunculus will be average or lower.
GoodRepresenting those who are doing better than average, is good rank. 80% of homunculus will be this rank or lower.
Very GoodOnly high tier homunculus hit this high. 90% will be at or below this rank.
ExcellentThose who are great rank are within the top 10% of homunculus. 95% will be at or below this rank.
AmazingOnly the rarest of homunculus will maintain stats this high. The top 5% will be in this rank.