It takes time to compute inflation. Details about how to compute inflation would be a seperate question.
However, what is used is this series, where it reads
Finally, the next grouping of data shows actually CPI figures from 1913 to present.
All Urban Consumers – (CPI-U) 1913-2022*
The computation is like this (for 1st of Nov, March to September is used: 2968.08/2875.04).
That is the inflation rate I showed in my other answer.
This answer replicates the calculation of the current value on the website of TreasuryDirect.