2 one dollar united america staes liberty 2000 and 2001

A few months ago, when we met in Madrid, the Erasmus colleagues from Darmstadt, Maite (I think) gave me a dollar coin from her last visit to the United States.
In popular iconography, the dollar bill may be the best known in the world; however historically, the currencies of a dollar have been very numerous:
During the nineteenth century and well into the crisis of 29, this coin was coined in silver, in imitation of the 8 Spanish Royals coin.
During the 1970s different dollar coins were minted, in non-noble metals: the Esenhower dollar and the Susan B. Anthony dollar.
In the year 2000 they issued a new dollar currency, representing on the obverse of Sacagawea (which also appears in a chapter of the Simpsons).
Like the two previous issues, they are currencies that have not achieved much popularity in the United States, and are used mostly in vending machines.
The coin has a surface finish with gold finish, but it seems that as soon as it circulates a little it breaks down and the color changes substantially.
Since 2007 a new dollar coin has been issued, with the obverse with the presidents of the United States, and although this dollar currency has continued in minting until 2008, in 2009 its design was changed.
As can be seen in the photograph, on the obverse appears a portrait of an Indian woman, with a child on her back, above the legend "LIBERTY", on the left "IN GOD WE TRUST" and on the right 2001, year of minting and the mint mark, Philadelphia P.
On the back, an eagle flying with the eagles extended and the legend "UNITED STATES OF AMERICA", 17 stars around the eagle and the legend "E PLURIBUS UNUM". Below, "ONE DOLLAR".
Specifically, the circulation of this coin, from 2001 and with the mint mark P, was 62.5 million pieces.