Social Security will announce its cost of living adjustment (COLA) for 2023 Thursday, which could be as high as 8.7%, the Senior Citizens League estimates. This would be the highest rise for seniors and those on disability since 1981, when Social Security beneficiaries got 11.2% more in their checks.

If the Senior Citizens League is right, the average benefit a retiree gets each month would rise by $144 a month to $1,656, up from $1,729.

The Social Security Administration bases its annual COLA adjustment on the Consumer Price Index for Urban Wage Earners and Clerical Workers, the CPI-W, which increased 8.7% in the past year.

In August, when the CPI read on headline inflation was 9.1%, the Senior Citizens League projected the COLA would be higher, 9.6%. The latest CPI, for August, is 8.3%.

The U.S. Bureau of Labor Statistics will announce the September CPI on Thursday.

“A COLA of 8.7% is extremely rare and would be the highest ever received by most Social Security beneficiaries alive today,” says Mary Johnson, author of the Senior Citizen League’s report and a policy analyst with the nonpartisan senior advocacy group. “There were only three other times since the start of automatic adjustments that it was higher.”

Two downsides to a steep COLA, however, are that it could disqualify some Social Security recipients from low-income programs, like food stamps, or push them into higher tax brackets, which can be steep for senior citizens.