[经] stable monetary unit assumption

wěn dìng huò bì dān wèi jiǎ dìng ㄨㄣˇ ㄉㄧㄥˋ ㄏㄨㄛˋ ㄅㄧˋ ㄉㄢ ㄨㄟˋ ㄐㄧㄚˇ ㄉㄧㄥˋ