'Thirty' in the Bible

Thirty and two years old was he when he began to reign; and he reigned eight years in Jerusalem.

In the thirty and seventh year of Joash king of Judah began Jehoash the son of Jehoahaz to reign over Israel in Samaria, and reigned sixteen years.

In the thirty and eighth year of Azariah king of Judah did Zachariah the son of Jeroboam reign over Israel in Samaria six months.

And Hezekiah king of Judah sent to the king of Assyria to Lachish, saying, I have offended; return from me: that which thou puttest on me will I bear. And the king of Assyria appointed unto Hezekiah king of Judah three hundred talents of silver and thirty talents of gold.

Josiah was eight years old when he began to reign, and he reigned thirty and one years in Jerusalem. And his mother's name was Jedidah, the daughter of Adaiah of Boscath.