each year vs annually

each year and annually both are adverbs.

Word	Noun	Adjective	Verb	Adverb
each year	No	No	No	Yes
annually	No	No	No	Yes

As adverbs, each year and annually are synonyms defined as:

Other synonyms of each year include every year, yearly.

As adverbs, each year and annually are synonyms defined as:

each year and annually: by the year; every year (usually with reference to a sum of money paid or received)

Other synonyms of each year include p.a., per annum, per year.

each year (adverb)	annually (adverb)
without missing a year	without missing a year
by the year; every year (usually with reference to a sum of money paid or received)	by the year; every year (usually with reference to a sum of money paid or received)