I don't know yearly sales figures for the original Xbox but Welfare has said that for USA sales XBS in 2024 sold less than the ORIGINAL Xbox sold in the years 2002-2004. It was Xbox's worst performance in the US other than 2001, 2005 and 2020. So only the years where they first launched, or a console was replaced have they done worse.
https://youtu.be/O4PRA18TFWY?si=WKKzTgD2n3gxaXN9