WASHINGTON — U.S. employers stepped up hiring last month, adding a healthy 227,000 jobs, and more Americans began looking for work, a sign that President Donald Trump has inherited a robust job market.

January's job gain was the best since September and exceeded last year's average monthly gain of 187,000, the Labor Department reported Friday.

The unemployment rate ticked up to a still-low 4.8 percent last month from 4.7 percent in December. But the rate rose for a mostly good reason: More Americans started looking for work, though not all of them immediately found jobs. The percentage of adults working or looking for jobs reached its highest level since September.

Yet some of the economy's weak spots remain: Average hourly wages barely increased last month. And the number of people working part time who would prefer full-time work rose.

January's jobs figures reflect hiring that occurred mainly before Trump was inaugurated on Jan. 20. Still, it was the first employment report to be released with Trump occupying the White House, and he seems sure to take a close interest in it.

As a candidate, Trump frequently argued that the government's jobs data exaggerated the health of the economy. He called the unemployment rate a "hoax" and said it declined after the recession under President Barack Obama mainly because many Americans stopped working or looking for work.

The biggest factor in that trend has been widespread retirements by the vast generation of baby boomers.

Measures of business sentiment indicate that many employers have adopted a more positive outlook since Trump's election victory in November. The president's promised tax cuts, deregulation and infrastructure spending have increased optimism that the economy's sluggish pace of growth will pick up.

The National Federation of Independent Business said its measure of small business optimism soared 38 points in December to its highest level since 2004. And the Conference Board's consumer confidence index jumped to a 15-year high in December before dipping slightly last month.

The Federal Reserve has taken notice. It inserted a reference to the improved consumer and business outlook in a statement it issued after its policymakers met this week. The Fed left its key interest rate unchanged but struck a slightly more upbeat tone about the economy.

The economy appears to be on firm footing, and the possibility of further stimulus from tax cuts and infrastructure spending could quicken inflation and lead the Fed to raise rates more rapidly, some economists say.

Joseph LaVorgna, an economist at Deutsche Bank, said he is optimistic that the economy will accelerate this year, in part because of Trump's policies. But he thinks hiring is more likely to accelerate later this year.

In the meantime, most recent economic data have been positive and have pointed to a pickup in growth this year after a lackluster 2016.

American factories expanded last month at their fastest pace in more than two years, according to a private survey of purchasing managers. Production and new orders rose at a healthy pace. And a gauge of hiring suggested that manufacturers may have added jobs at a faster pace in January.

Businesses are also spending more on such high-priced items as industrial machinery, computers and autos, a government report last week showed.

Consumers are showing renewed health, too. They boosted their spending in December by the most in three months.