The bases. To measure increases in the cost-of-living for annual automatic increase purposes, we use either:

The revised Consumer Price Index (CPI) for urban wage earners and clerical workers as published by the Department of Labor, or

The average wage index (AWI), which is the average of the annual total wages that we use to index (i.e., update) a worker's past earnings when we compute his or her primary insurance amount (§ 404.211(c)).

Effect of the OASDI fund ratio. Which of these indexes we use to measure increases in the cost-of-living depends on the Old-Age, Survivors, and Disability Insurance (OASDI) fund ratio.

OASDI fund ratio for years after 1984. For purposes of cost-of-living increases, the OASDI fund ratio is the ratio of the combined assets in the Federal Old-Age and Survivors Insurance Trust Fund and the Federal Disability Insurance Trust Fund (see section 201 of the Social Security Act) on January 1 of a given year, to the estimated expenditures from the Funds in the same year. The January 1 balance consists of the assets (i.e., government bonds and cash) in the Federal Old-Age and Survivors Insurance Trust Fund and the Federal Disability Insurance Trust Fund, plus Federal Insurance Contributions Act (FICA) and Self-Employment Contributions Act (SECA) taxes transferred to these trust funds on January 1 of the given year, minus the outstanding amounts (principal and interest) owed to the Federal Hospital Insurance Trust Fund as a result of interfund loans. Estimated expenditures are amounts we expect to pay from the Old-Age and Survivors Insurance and the Disability Insurance Trust Funds during the year, including the net amount that we pay into the Railroad Retirement Account, but excluding principal repayments and interest payments to the Hospital Insurance Trust Fund and transfer payments between the Old-Age and Survivors Insurance and the Disability Insurance Trust Funds. The ratio as calculated under this rule is rounded to the nearest 0.1 percent.

Which index we use. We use the CPI if the OASDI fund ratio is 15.0 percent or more for any year from 1984 through 1988, and if the ratio is 20.0 percent or more for any year after 1988. We use either the CPI or the AWI, depending on which has the lower percentage increase in the applicable measuring period (see § 404.274), if the OASDI fund ratio is less than 15.0 percent for any year from 1984 through 1988, and if the ratio is less than 20.0 percent for any year after 1988. For example, if the OASDI fund ratio for a year is 17.0 percent, the cost-of-living increase effective December of that year will be based on the CPI.