perennial [Adjective] + difficulty [Noun]

Strength Strength Dispersion
A:
5
CHISQ:
26.58
AWT:
20,621,965
TTEST:
1.92
G2:
15.24
FAWT:
2.64
MI:
2.84
LOGLOG:
6.6
JD:
0.56
MI3:
7.48
DICE:
0.08
RANGE: