The more than 20,000 visitors to the District this week for the International AIDS Conference downtown are expected to pump more than $33 million into the local economy, according to the city's tourism bureau.

The conference, which started July 20 and runs through Friday, has drawn more than 24,000 registered delegates so far from 183 countries. The spending estimates were based on Destination Marketing Association International's economic impact formula, which calculates total spending based on factors that include the number of visitors, where they're from and where the conference is located, according to Destination DC.

The fact that more than half of the conference's registrants are international helps boost spending, said Greg O'Dell, CEO of Events DC, the city's sports and entertainment arm. He said that although previous conventions here have attracted attendees from other countries, this is the first convention for an organization that is based abroad, therefore attracting scores more international visitors than is typical.

By the numbers
• 24,000 registered attendees
• 183 countries represented
• 11,695 U.S. delegates (most represented)
• 644 South Africa delegates (2nd-most represented)

"The international base tends to stay longer and spend more money," O'Dell said, adding that the surge is coming at a time when the convention business is typically slow.

"Our peaks are mid-February or March to mid-June ... then August to about mid-November," O'Dell said. "So, July is not typical."

According to the breakdown, attendees are spending anywhere from $1,400 to $2,000 per person for their hotel stay, meals and ancillary spending while here in the District.

Because of the length of the convention, many visitors said they were staying at least 10 days to allow themselves some sightseeing time before and after the event. Sherri Pooyack, who works with indigenous populations living with AIDS/HIV in Canada, said her group numbers at least 20 people and they've ventured out to explore the city nearly every night they've been here.

"We've seen the Lincoln Memorial two times since we've been here," she said adding that their group has also dined out at popular D.C. restaurants in Penn Quarter and Chinatown.