U.S. employers added 217,000 jobs in May, a substantial gain for a fourth straight month, fuelling hopes that the economy will accelerate after a grim start to the year.

Monthly job growth has now averaged 234,000 for the past three months, up sharply from 150,000 in the previous three. The unemployment rate, which is calculated from a separate survey, remained 6.3 per cent in May.

The report on Friday from the Labor Department signalled that the U.S. economy is steadily strengthening and outpacing struggling countries in Europe and Asia. Consumers are showing more confidence. Auto sales have surged. Manufacturers are expanding solidly. U.S. service companies are growing more quickly.

And the job market has now reached a significant milestone.

Nearly five years after the Great Recession ended, the economy has finally regained all the jobs lost in the downturn.

More job growth is needed, though, because the U.S. population has grown nearly 7 per cent since then.

Economists at the liberal Economic Policy Institute have estimated that 7 million more jobs would have been needed to keep up with population growth.

In addition, pay growth remains below levels typical of a healthy economy.

Average wages have grown roughly 2 per cent a year since the recession ended, well below the long-run average annual growth rate of about 3.5 per cent.