'Twentieth' in the Bible

The words of Nehemiah the son of Hachaliah. And it came to pass in the month Chislev, in the twentieth year, as I was in Shushan the fortress,

And it came to pass in the month Nisan, in the twentieth year of Artaxerxes the king, that wine was before him, and I took up the wine and gave it to the king. Now, I had never been 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 thirty-second year of Artaxerxes the king, twelve years, I and my brethren have not eaten the bread of the governor.