WASHINGTON - Social Security checks are going up 2 percent in 2018, the U.S. government announced Friday.

It's the first substantial raise in years.

More than 66 million Americans receive Social Security payments. Most recipients are seniors over age 65, but some payments also go to the severely disabled and orphans. The average check is currently $1,377 a month, meaning next year's increase will raise the typical payment by $27 a month.

For Sandy Lacoss of Woodstock, Vt., the pay bump can't come soon enough.

"We need more money to live on," said Lacoss, a 71-year-old retired cleaner. "My rent goes up every year. I really can't afford it."

Social Security checks rose 0.3 percent in 2017. In 2016, the checks didn't go up at all, leaving many seniors saying they are struggling to keep up on their bills. There hasn't been an increase greater than 2 percent since 2012.

The raise is a cost of living adjustment (COLA) that's meant to keep up with higher costs of everything from rent to medications. But many seniors think the government's calculations are flawed.

"If you polled seniors, 10 out of 10 would say the COLA is not keeping up with their costs," said Gary Koenig, vice president of financial security for AARP.

But others say the COLA formula, which has been used since 1975, is fair.

"Seniors are not getting slighted," said Charles Blahous, who served as the public trustee for Social Security and Medicare from 2010 through 2015 and is now a researcher at the Mercatus Center.

The COLA isn't meant to be a merit increase, Blahous said. He points out that years where there's been no increase in the COLA are actually good for seniors because those were years when prices weren't rising (or even fell), yet seniors don't get their checks reduced. The 2018 rise is larger than in past years, partly because Hurricanes Harvey and Irma caused a jump in gas and other prices in September.

The Social Security Administration bases the COLA on a measure of inflation called CPI-W, a statistic that captures how fast costs are rising for workers. Most seniors are retirees who no longer have jobs. Health care is their biggest expense, and it's one of the fastest rising costs in America. Medicare Part B premiums are expected to rise in 2018, eating up much of the Social Security increase for some seniors.

Lacoss has rheumatoid arthritis and asthma. She gets dizzy sometimes and broke her arm a few years ago from a fall. Her doctor suggested that she get a Lifeline, a medical alert system, but she asked him how she was supposed to pay for it.

"I wish I could go to work, but the doctors won't let me," Lacoss said. She lives off about $900 a month - $691 a month from Social Security and $207 from a pension from an old job - putting her just below the poverty line of $12,060 a year for one person.

Social Security is a financial lifeline for many. The monthly payments lifted over 26 million Americans out of poverty last year, according to the Census Bureau, making it the most effect anti-poverty program the government has.

"The income older Americans get from Social Security is critical in keeping them out of poverty," Koenig said. About half of older Americans rely on Social Security for 50 percent or more of their income, AARP found.

President Donald Trump vowed during his campaign not to cut Social Security benefits.

Lacoss has already been informed that her rent payment is going up in December. With no children or spouse, she is on her own to make her meager budget work. She exhausted her savings paying for medical bills and car repairs in recent years. She's thankful for a local food bank, which helps her out with groceries.

Her only splurge is her cat, Sassy Girl.

"She's my buddy and I'm her buddy," says Lacoss. "I'll go without before she will have to go without."