noun, adverb
Indicates that something happens each year or is done on a yearly basis. Can be used as a noun or adverb.
この祭りは年ごとに開かれる。
This festival is held every year.
年ごとの収入を記録している。
I record my yearly income.
毎年 is the most common way to say 'every year' in modern Japanese. 年ごと is less frequent and can emphasize a repeated yearly cycle or a per-year basis.
年々 means 'year by year' with a nuance of gradual change over the years. 年ごと simply states that something occurs each year without implying change.
Compound of 年 (とし, 'year') and ごと ('each, every'). The suffix ごと attaches to nouns to indicate 'each' or 'every'.