Nearly 250,000 tickets sold by the Washington Nationals have gone unused at Robert F. Kennedy Memorial Stadium, a no-show rate that is slightly higher than normal for professional teams and could mean that the District earns less revenue than expected.

The Nationals sold an average of 32,019 tickets for their first 33 games, from their home opener in April through June 12, a pace that puts them on track to meet their preseason projection of about 2.5 million tickets for the season.

But the average number of people who attended those games was 24,679, according to data provided by the D.C. Sports & Entertainment Commission, which operates RFK. This figure, known as the turnstile count, is rarely divulged by professional teams but is closely monitored in the sports industry.

The rate of unused tickets at RFK was 23 percent, slightly higher than the 15 to 20 percent that a professional team should expect, industry analysts said. And the difference means less money for the city in taxes from parking spaces, hot dogs and all the other things fans buy at RFK.

Team officials said they are not disappointed by the crowds and predict that more fans will use their tickets during the summer because schools are in recess.

"We are not concerned at this point," said David Cope, the Nationals' vice president for sales and marketing, who has worked for several professional teams. "The lowest months of turnstile attendance are April, May and early June, before school lets out and before the weather turns."

In large part because of solid ticket sales, the Nationals are expected to make a pretax profit of $20 million, a remarkable turnaround for a franchise that lost about $10 million last season. The District government receives a 10 percent sales tax on tickets.

But the city's revenue also is based on how many fans pay for parking, food, beverages and merchandise. The city receives a 12 percent tax on parking services and 10 percent on all food, beverage and merchandise sales. This in-stadium revenue is crucial because officials intend to use that money to help finance construction bonds to build a $535 million stadium project along the Anacostia River.

Julia Friedman, deputy chief financial officer in the D.C. Office of Revenue Analysis, said District planning officials received a report last year from consultants who estimated that a baseball team playing at RFK would sell an average of 36,000 tickets a game in its first season. Turnstile attendance would be about 33,000 a game, the report said.

Based on those numbers, the city expected to earn $10.5 million in tax revenue in the first year, Friedman said.

"This was a planning document," she said. "It was sort of a base line."

The report stated that in the team's second and third seasons at RFK, ticket sales and actual attendance would decline each year, Friedman said. Then they would bump up to 38,000 tickets sold per game and an average attendance of 35,000 in a new stadium.

The unpredictable aspect of how many fans use their tickets might make Wall Street leery of giving the city a good rate on bonds that are financed by tax revenue from the stadium sales, said Natwar M. Gandhi, the District's chief financial officer. He used this argument when he recommended that the city accept a private financing plan from Deutsche Bank. No decision has been made.

The practice of announcing the paid attendance instead of the turnstile count is common across the major professional leagues, in part because teams want to reflect the largest crowds possible to help marketing. Also, the head count used to be harder to tabulate. The D.C. Sports & Entertainment Commission uses a ticket-scanning system developed by Ticketmaster to keep track of the daily crowd as fans enter RFK's turnstiles. An electronic scanner reads a bar code on each ticket.

Nationals players have said repeatedly that they have been impressed by the size and passion of game-day crowds, which dwarf the number of fans who showed up in Montreal, where the team played last year.

But no-shows were notable even as the Nationals moved into first place during a 10-game winning streak early this month. With each game at RFK, the Nationals sold an average of 32,014 tickets, but the number of fans in the stadium averaged 23,585.

For a thrilling, 11th-inning victory over the Florida Marlins on June 3, the team announced a paid attendance of 29,439 on a night that was cloudy and had the potential for rain. The actual crowd was 16,723.

Vincent Morris, spokesman for Mayor Anthony A. Williams (D), said city officials believe that the Nationals' attendance will improve as fans become more familiar with the team and the routine of going to games.

"The consensus is that the numbers will go up," Morris said. "People are still being introduced to the Nationals."

About 22,000 people or companies purchased season ticket plans, a number that pleased Nationals officials. But Colin Mills, president of a Nationals fan club, said he believes that corporations, not rabid baseball fans, bought a large share of season tickets and often fail to use the tickets -- including those for the prime seats close to the field.

"We call them 'Johnny Jaguar,' the typical K Street lobbyists who buy all the tickets and don't show for the game," Mills said. "Based on the breathless preseason hyperbole that the team would sell out every night, that's not happening."

Allen R. Sanderson, who teaches sports business at the University of Chicago, said many fans and companies probably bought tickets before the season began, figuring the team would be bad because the Expos were bad.

These ticket buyers did not necessarily want to go to games at 44-year-old RFK, Sanderson said, but wanted to "be at the head of the queue for a new stadium and when the team gets better."

Andrew Zimbalist, a professor of economics at Smith College in Massachusetts who has written about sports business, said the Nationals also have been hurt by the lawsuit between Comcast and Baltimore Orioles owner Peter G. Angelos, which has kept many games off television.

"You need to have television coverage to get people interested in the team," Zimbalist said. "The way people do it is watch it on TV, get excited about the team and say, 'I want to see it in person.' "

Staff writer Barry Svrluga contributed to this report.