'Eighteenth' in the Bible

In the eighteenth year of king Jeroboam -- Abijah reigneth over Judah;

And in the eighteenth year of his reign, to purify the land and the house he hath sent Shaphan son of Azaliah, and Maaseiah head of the city, and Joah son of Johaz the remembrancer, to strengthen the house of Jehovah his God.

In the eighteenth year of the reign of Josiah hath this passover been made.