Fourth-quarter revenue fell 7.1% at Administaff Inc. (NYSE: ASF) to $395.9 million from $426.0 million in the same period last year.

The Kingwood TX-based professional employer organization reported that average number of worksite employees paid per month in the fourth quarter fell 9.9% while revenue per worksite employee per month rose 3.1%.

Fourth-quarter gross margin narrowed to 15.5% from 20.6% in the year-ago quarter.

Administaff posted a fourth-quarter net loss of $2.8 million compared with net income of $9.7 million in the fourth quarter of 2008.

Full-year revenue fell 4.1% to $1.65 billion from $1.72 billion in 2008. Gross margin fell to 17.4% from 19.9%.

Full-year net income fell 63.8% to $16.6 million in 2009 from $45.8 million in 2008.

Administaff Inc. (NYSE: ASF)
For the fourth quarter ended Dec. 31, 2009, compared with the same period in 2008.
Revenue: $395.9 million, -7.1%
Net loss: $2.8 million vs. net income of $9.7 million

For the full year ended Dec. 31, 2009, compared with the previous year.
Revenue: $1.65 billion, -4.1%
Net income: $16.6 million, -63.8%