incidence vs relative incidence

incidence and relative incidence both are nouns.

Word	Noun	Adjective	Verb	Adverb
incidence	Yes	No	No	No
relative incidence	Yes	No	No	No

As nouns, incidence and relative incidence are synonyms defined as:

incidence and relative incidence: the relative frequency of occurrence of something

incidence (noun)	relative incidence (noun)
the striking of a light beam on a surface	the relative frequency of occurrence of something
the relative frequency of occurrence of something