A private survey says U.S. services companies grew in January at the slowest rate in nearly two years, as global economic challenges are showing some signs of spreading to consumers.

The Institute for Supply Management said that its services index fell to 53.5 last month from 55.8 in December. The January figure was the lowest since February 2014, when it was 52.6. Still, any reading above 50 signals that services firms are expanding.

"It's a little bit of a cooling off," said Anthony Nieves, chair of the ISM non-manufacturing business survey committee. But Nieves stressed, "As long as we're staying above the 50 baseline, things are still going in the right direction."

The U.S. economy is off to a rocky start in 2016. Stocks have plunged. Manufacturing activity fell in January for the fourth consecutive month. U.S. growth economic growth slowed sharply in the final months of 2015. China, Japan, Europe and Brazil face more immediate financial challenges.

Still, the U.S. services sector has been a source of stability amid the turmoil. The ISM index has been expanding for the past six years, its gains dovetailing with the recovery from the recession. An improving services sector has coincided with a healthy dose of hiring, as employers added 292,000 workers to their payrolls in December. The unemployment rate held at 5 percent.

Economists say the government jobs report for January to be released Friday should show another 200,000 jobs added.

The majority of respondents to the survey for the services index were positive about business conditions. But they expressed concern about the global economy and turbulent stock market eroding consumer confidence.

The services survey showed continued but slower growth for business activity, new orders and employment.

Falling oil prices have hurt U.S. exports and factories, yet that has meant more breathing room for consumers, whose wages have barely budged. Gasoline costs have tumbled 13 percent over the past year to a national average of $1.79 a gallon, according to the AAA Daily Fuel Gauge.

The troubled global economy walloped the United States in the October-December quarter of last year. Annual economic growth slowed to a rate of 0.7 percent from 2 percent in the prior quarter. Consumer spending, business investment and exports each decelerated as 2015 ended.

Manufacturing remains the primary drag.

The ISM's index of factory activity inched up to 48.2 from a revised 48 in December, but any reading below 50 signals a contraction. The index has stayed below 50 since September.

The ISM is a trade group of purchasing managers. Its services survey covers businesses that employ the vast majority of workers, including retail, construction, health care and financial services companies.