'Eighteenth' in the Bible

And Jehoram son of Ahab hath reigned over Israel, in Samaria, in the eighteenth year of Jehoshaphat king of Judah, and he reigneth twelve years,

And it cometh to pass, in the eighteenth year of king Josiah, the king hath sent Shaphan son of Azaliah, son of Meshullam, the scribe, to the house of Jehovah, saying,

but in the eighteenth year of king Josiah, hath this passover been made to Jehovah in Jerusalem.