'Twentieth' in the Bible

The words of Nehemiah son of Hacaliah:During the month of Chislev in the twentieth year, when I was in the fortress city of Susa,

During the month of Nisan in the twentieth year of King Artaxerxes, when wine was set before him, I took the wine and gave it to the king. I had never been sad in his presence,

Furthermore, from the day King Artaxerxes appointed me to be their governor in the land of Judah—from the twentieth year until his thirty-second year, 12 years—I and my associates never ate from the food allotted to the governor.