WASHINGTON — Good news for seniors: Millions of Americans who rely on Social Security are projected to receive their biggest payment increase in years this January.

Bad news for seniors: It's just a 2.2 percent increase, or about $28 a month for the average recipient.

The trustees who oversee Social Security and Medicare released their 2018 projections Thursday, along with their annual warning about the long-term financial problems of the federal government's two bedrock retirement programs.

Social Security recipients have gone years with tiny increases in benefits because inflation has been low or non-existent. This year they received an increase of 0.3 percent, after getting nothing last year. The last time they got a bigger increase was in 2012, when the hike was 3.6 percent.

In recent years, many Social Security recipients have seen their cost-of-living adjustments erased by higher premiums for Medicare Part B. The trustees say that shouldn't be a problem next year. They project that Medicare Part B premiums will remain unchanged — $134 a month for most, though retirees with higher incomes pay more.

Both Social Security's cost-of-living adjustment and the Medicare Part B premium are to be announced in the fall.

More than 61 million retirees, disabled workers, spouses and surviving children receive Social Security benefits. The average monthly payment is $1,253. Medicare provides health insurance to about 58 million people, most of whom are at least 65 years old.

Unless Congress acts, the trust funds that support Social Security are estimated to run dry in 2034, the same year as last year's projection. Medicare's trust fund for inpatient care is projected to be depleted in 2029, a year later than last year's forecast.

If Congress allows either fund to be depleted, millions of Americans living on fixed incomes would face steep cuts in benefits.

Neither Social Security nor Medicare faces an immediate crisis — they both currently have surpluses. But the trustees warn that the longer Congress waits to address the programs' problems, the harder it will be to sustain Social Security and Medicare without steep cuts in benefits, big tax increases or both.

For example, in 2034, Social Security is projected to have a $546 billion shortfall, which would grow to more than $3 trillion in the first five years.