'Year' in the Bible

The words of Nehemiah the son of Hacaliah. Now it happened in the month Chislev, in the twentieth year, as I was in Shushan the palace,

It happened in the month Nisan, in the twentieth year of Artaxerxes the king, when wine was before him, that I took up the wine, and gave it to the king. Now I had not been [before] sad in his presence.

Moreover from the time that I was appointed to be their governor in the land of Judah, from the twentieth year even to the two and thirtieth year of Artaxerxes the king, [that is], twelve years, I and my brothers have not eaten the bread of the governor.

and if the peoples of the land bring wares or any grain on the Sabbath day to sell, that we would not buy of them on the Sabbath, or on a holy day; and that we would forego the seventh year, and the exaction of every debt.

We cast lots, the priests, the Levites, and the people, for the wood offering, to bring it into the house of our God, according to our fathers' houses, at times appointed, year by year, to burn on the altar of Yahweh our God, as it is written in the law;

and to bring the first fruits of our ground, and the first fruits of all fruit of all kinds of trees, year by year, to the house of Yahweh;

But in all this [time] I was not at Jerusalem; for in the two and thirtieth year of Artaxerxes king of Babylon I went to the king: and after certain days asked I leave of the king,