jährlichem
jährlichem is a declined form of the German adjective jährlich, meaning annual or yearly. It is not a separate word, but the specific ending used in certain grammatical contexts.
In German, adjectives agree with case, gender, number, and definiteness. jährlichem occurs in the dative singular
Common, everyday counterparts are the unchanged adverbial or attributive forms jährlich, jährlich rather than the occasional
Etymologically, jährlich derives from Jahr (year) with the suffix -lich, producing an adjective that denotes periodicity
See also: jährlich, alljährlich, Jahresrhythmus, Jahresplanung, German grammar declension.