U.S. workers saw surprisingly large increases in pay at the end of 2004, according to a new report from the government that takes a comprehensive look at employment and wage trends across 317 of the country's largest counties.

The Labor Department report said weekly salaries rose an average of 5.7% in the fourth quarter from a year earlier. The gain seemed to be bolstered by commissions and end-of-year bonuses, which are included in the counts.

The report showed wages are growing, from suburban areas like Williamson County, near Austin, Texas, to big cities like New York. It also helped clarify a muddled national picture on the state of worker pay. Economists have been puzzled for months about why national income seems to be rising at a healthy pace while measures of hourly wages are barely keeping up with inflation.

The latest report lends weight to the argument that end-of-year bonuses and commissions were a factor, economists say.

The statistics showed that weekly wages averaged $812 throughout the nation. Workers in Williamson saw the biggest increases in weekly wages, with a 17.8% jump to $893 from a year earlier. Williamson County, the home of Dell Inc., is benefiting from the recovery in the tech sector and from robust single-family housing construction, according to Moody's Investors Service.

The county of Rutherford, Tenn., near Nashville, saw employment increase 8.9%, the biggest percentage employment gain in the period. Maricopa County (which includes Phoenix) had the biggest actual gain in new jobs, 75,700 in December 2004 compared with a year earlier.

Dave Iaia, a regional economist with Global Insight, a Waltham, Mass., forecasting firm, says job creation tended to be fastest in warm-weather counties that attracted lots of new families, such as Florida, Arizona and Nevada. Population expansion in those areas is promoting job growth in service sectors such as education, health and tourism, he says.

Joseph Carson, an economist at Alliance Capital, said many of the counties with large wage gains also had strong housing markets. "There could have been a lot of commissions paid out on real-estate transactions and year-end bonuses tied to those sales."

The largest declines in employment occurred in Wayne, Mich., where employment was down 12,600, and Allegheny, Pa., where employment was down 3,900. No county experienced year-over-year declines in average weekly wages, although Kalamazoo, Mich., had the smallest increase in wages, at 0.5%, followed by the 0.7% rise in Richmond, N.Y.

Separately, the Commerce Department said housing starts were unchanged at a seasonally adjusted 2.004 million annual rate last month. Permits for future building rose by 2.4% in June to a 2.111 million annual rate after falling a revised 4% in May.

"We have to settle for housing demand that is torrid rather than scalding," RBS Greenwich Capital Markets economist Stephen Stanley said. "The bottom line is that the housing sector is still extremely strong."

Low financing costs and concern that lending rates might escalate later this year are driving home-buying. According to Freddie Mac, the average rate on a 30-year fixed mortgage in June was 5.58%, the lowest monthly level since March 2004's 5.45%. Rates have stayed low despite a year-long campaign by the Federal Reserve to increase short-term borrowing costs.

The latest available government data show new-home sales rose 2.1% to a 1.271 million annual rate during May. The ratio of houses for sale to houses sold was 4.2. With supplies lean and demand hot, prices for houses in the U.S. have been rising, averaging $281,400 in May -- 8.2% above May 2004's $206,400.

With demand still high, homebuilders remain optimistic about the housing market. The National Association of Home Builders' index for sales of new, single-family homes fell to 70 in July from a revised 72 in June. When the index exceeds 50, the number of builders surveyed who expect good sales outnumber those who expect poor sales.

Regionally, home construction last month rose 11.4% to 1,003,000 in the South after dropping 11.9% in May. Construction fell 0.5% to 185,000 in the Northeast, 12.1% to 335,000 in the Midwest, and 10.4% to 481,000 in the West.