Definitions for falloffˈfɔlˌɔf, -ˌɒf
Random House Webster's College Dictionary
a decline in quantity, vigor, etc.
Origin of falloff:
slump, slack, drop-off, falloff, falling off(noun)
a noticeable deterioration in performance or quality
"the team went into a slump"; "a gradual slack in output"; "a drop-off in attendance"; "a falloff in quality"
A reduction or decline.