Azariah's 39th Year (Judah); Zechariah Ends 6 Month Reign (Israel)—II Kings 15:8, 13, 17

On the Gregorian calendar (the one you might have on your wall) the year was 705 BC.
On the Hebrew calendar, sometimes called the biblical calendar, the year was 3342 AM.
RELATED VERSES
2 Kings 15:8 New King James Version (NKJV)
8 In the thirty-eighth year of Azariah king of Judah, Zechariah the son of Jeroboam reigned over Israel in Samaria six months.
2 Kings 15:13 New King James Version (NKJV)
Shallum Reigns in Israel
13 Shallum the son of Jabesh became king in the thirty-ninth year of Uzziah king of Judah; and he reigned a full month in Samaria.
2 Kings 15:17 New King James Version (NKJV)
17 In the thirty-ninth year of Azariah king of Judah, Menahem the son of Gadi became king over Israel, and reigned ten years in Samaria.