'Year of' in the Bible

Then in the month of Nisan, in the twentieth year of King Artaxerxes, when wine was brought to me, I took the wine and gave it to the king. Previously I had not been depressed in the king's presence.

From the day that I was appointed governor in the land of Judah, that is, from the twentieth year until the thirty-second year of King Artaxerxes -- twelve years in all -- neither I nor my relatives ate the food allotted to the governor.

During all this time I was not in Jerusalem, for in the thirty-second year of King Artaxerxes of Babylon, I had gone back to the king. After some time I had requested leave of the king,