https://www.irs.gov/newsroom/irs-provides-tax-inflation-adju...
IRS provides tax inflation adjustments
And links to https://www.irs.gov/pub/irs-drop/rp-20-45.pdf
"This revenue procedure sets forth inflation-adjusted items for 2021 for various provisions of the Internal Revenue Code of 1986 (Code)"
It's states adjusting for inflation for the tax year beginning March 2021. The document came out in October 2020 when inflation was 1.2%, I'm not sure when they adjust it and you may disagree with the measure of inflation
The year before was November 2019
https://www.irs.gov/pub/irs-drop/rp-19-44.pdf
Here's the one for 2021/2 (Nov 29th 2021)
https://www.irs.gov/irb/2021-48_IRB
Married Individuals Filing Joint Returns, lowest and highest bands:
Thresholds for tax year 2021/2 goes from 19750 to 19900 (0.7%) at one end, and from 622050 to 628300 at the other (1%)
Thresholds for tax year 2022/3 goes from 19900 to 20550 (3.27%) at one end, and from 628300 to 647850 at the other (3.11%)