WASHINGTON – Social Security benefits will rise 1.5 percent in January, giving millions of retired and disabled workers an average raise of $19 a month to keep up with the cost of living.

The increase is among the smallest since automatic adjustments were adopted in 1975, and reflects the fact that consumer prices haven’t gone up much in the past year. The annual cost-of-living adjustment, or COLA, is based on a government measure of inflation that was released Wednesday.

Automatic COLAs were adopted in 1975 so that benefits for people on fixed incomes would better keep pace with rising prices. Some advocates for older Americans, however, complain that the COLA sometimes falls short, especially for people with high medical costs.

The COLA affects benefits for more than one-fifth of the country: nearly 58 million Social Security recipients, as well as benefits for millions of disabled veterans, federal retirees and people who get Supplemental Security Income, the disability program for the poor.

Social Security pays retired workers an average of $1,272 a month. A 1.5 percent raise comes to about $19.

Benefits are based on lifetime earnings. The more you make, the higher your benefit — to a point. For someone who retired this year at age 66, the maximum monthly benefit is $2,533. That person will get a raise of about $38 a month.

The COLA is calculated by comparing consumer prices in July, August and September each year with prices in the same three months from the previous year. If prices go up over the course of the year, benefits go up, starting with payments delivered in January.

Since 1975, annual Social Security raises have averaged just over 4 percent. Next year will mark only the seventh time the COLA has been less than 2 percent. This year’s increase was 1.7 percent. There was no COLA in 2010 or 2011 because inflation was too low.

Associated Press