Private-sector payrolls expanded at a very strong pace in December, according to data released Wednesday. Private-sector jobs in the U.S. rose by 297,000 last month, according to a national employment report published by payroll giant Automatic Data Processing Inc. (ADP) and consultancy Macroeconomic Advisers. Economists had expected ADP to report a job gain of 100,000 in December–one third of the actual number. The estimated change in employment for November was revised to show a rise of 92,000 versus the 93,000 increase first reported. The report said the gain “suggests nonfarm private employment grew very strongly in December, at a pace well above what is usually associated with a declining unemployment rate.”