WASHINGTON -- The National Association of Realtors has revised U.S. January existing home sales data sharply higher, saying sales rose 3.8% in the month to a 5.13 million unit annual rate. The realtors' group originally said sales of previously owned homes fell 6.6% in January to a 4.65 million unit rate.

"When upgrading to new software in May 2000, a software vendor failed to update data covering the first four months of 2000," NAR said in a statement on its website.

"Monthly sales rates and inventory levels are affected most by the error; there are no revisions to price data," the group said, adding that "although most revisions are minor" the error resulted in under-reporting of sales rates for the first two months of 2000 as well as January 2001.

NAR said December existing home sales were revised to 4.94 million units from 4.98 and January 2000 sales to 5.03 million from 4.54 million. The group said it discovered the error this month.