U.S. companies stepped up hiring in May, a private survey found, evidence that employers remain confident in the economy even after it contracted at the start of the year.

Payroll processor ADP says businesses added 201,000 jobs last month, up from just 169,000 in the previous month. April's increase was the smallest in a year and a half.

The figures suggest that the economy is recovering after it shrank at a 0.7 percent annual rate in the first quarter. On Friday, the government will issue its official jobs report for May. Economists forecast it will show that employers added 227,000 jobs, and the unemployment rate remained 5.4 percent.

The ADP survey covers only private businesses, however, and frequently diverges from the official figures.