"Clearly, we have a great asset in the downtown," said Richard Bradley, the business improvement district's executive director. "In many respects, it's the fuel that's allowing the mayor and the council to meet the social and economic needs of the city."

He cautioned, however, that the area faces formidable competition from the suburbs and that the District government needs to continue to invest resources downtown, including lobbying Metro to add subway cars and reinvigorating K Street.

"The goose has laid the golden egg, but the goose can get tired," Bradley said of downtown. "It needs to be supported so it will continue to provide the level of growth essential for a city with a structural deficit."

Once desolate and forlorn, the District's downtown has been revived by development including Verizon Center on Seventh Street NW.

Over the past eight years, developers constructed more than 11 million square feet of office space downtown, accounting for nearly 60 percent of the new commercial office space built in the city, the study found.

Yet the report also points out that the development did not come without a cost to taxpayers. From 1996 to 2005, according to the study, the District spent $400 million supporting a host of projects, including Verizon Center, Gallery Place, the new convention center and the Sidney Harman Hall theater.

"These public investments worked to leverage $10 billion in private investment, which has produced a public benefit to the entire city," the report said.

The Downtown DC Business Improvement District is a private, nonprofit organization founded to promote and serve the city's central business section, a 140-block area that extends from Massachusetts Avenue on the north to the Mall on the south and from Louisiana Avenue on the east to the White House on the west. The organization pays for the services with money generated by a tax on commercial property owners within its boundaries.

The study also found:

• The District has added 67,400 jobs since 1996, more than 95 percent of them downtown.
• Legal services was the fastest-growing job sector, up 42 percent from 2003 to 2006. Another growing sector was retail jobs, which increased by 30 percent over the same period.
• The average salary of a job downtown was $75,000 in 2006, a 20 percent increase from 2003
• Downtown office rents are among the highest in the nation. Class A office space rents at an average of $56 per square foot in the District, placing the city third behind Manhattan, which rents at $72 per square foot, and Boston, at $64 per square foot.