In a quarter of the nations surveyed, outbound flows were greater than all their foreign aid and direct investment combined. In Togo, for example, for every dollar that entered in foreign aid and direct investment more than five dollars left through illicit channels.

Liberia’s level of illicit outflows was three times the country’s total tax revenue. In the Republic of Congo, five times as much left the country in illegal outflows as the government spent on healthcare.

In Equatorial Guinea, the average outbound flow amounted to nearly $4,000 for every man, woman and child.

“It could have been invested in the country. It could have been turned into job creation. It’s a lost opportunity for these countries,” said Joseph Spanjers, the report’s lead author.

“We looked at exclusively these poorest countries because typically they don’t show up in our annual reports.”

The report found that illicit outflows correlate with high income inequality and lower levels of development.

But the prevalence of dirty money did not correlate with the strength of public sector institutions and the perception of corruption, something Spanjers said he found surprising.

“IFFs tend to be more private sector driven,” he said, noting that the annual Corruption Perceptions Index, produced by Transparency International, focused more on the public sector.

In releasing its report, GFI called for policy makers around the world to adopt new transparency measures.

Foreign aid donors should help developing countries to enforce customs laws, it said, and the UN should adopt the goal of reducing illicit financial flows by half over the next 15 years.

Representatives from the UN Development Program and the International Monetary Fund did not immediately respond to requests for comment.

The cumulative dollar amounts produced annually by GFI for the flow of dirty money are 20 percent derived from “leakages” in the balance of payments — such as bank transfers not accounted for on one end — with the rest coming from trade misinvoicing, according to Spanjers.

This meant the organization’s review was unable to capture things such as cash transactions, and that the true cost of illicit outflows is higher than the figures reported, according to Spanjers.

“We would characterize these estimates as conservative,” he said.

However, the methods of trade misinvoicing can present challenges that do not have perfect solutions, according to Simon J. Pak, associate professor of finance at Penn State.

The key is to determine what a transaction ought to be worth so that anomalies can be spotted, he said.

Pak said he favors “interquartile pricing,” in which a range of acceptable prices are derived from transaction or market data. Within the top or bottom 25 percent, an admittedly very broad range, transaction values may be deemed suspicious, according to Pak, who was not involved in the GFI report.

GFI’s method works on the assumption that transaction values reported by customs officials in developed countries are closer to the truth than those in less developed countries, he said.

“That’s a big assumption,” Pak said, noting that transaction reporting in developed countries can be inaccurate, too.

In January, the British drug maker GlaxoSmithKline settled a case in Canada in which local authorities rejected the company’s tax deductions of payments for shipments of a drug that generic companies bought at a lower price.

“If all the US data was correct, there’d be no reason for the IRS to have an entire transfer pricing division,” he said.

However, Pak said either method involved inaccuracies and GFI’s numbers might be the best available.

“It may not be precise but at least it’s good on the order of magnitude,” said Pak.

“And they are sufficiently large that we ought to be concerned.”

Top photo: Citizens of India are among the biggest victims of corruption via illicit outflows. Here, an Indian laborer sorts through heaps of waste at the city’s lone landfill site in Srinagar, the summer capital of Indian administered Kashmir, India, in April. Although the Indian economy has seen significant growth, there are still millions of people who survive on less than $1 (63 INR) a day. (Photo by Yawar Nazir/Getty Images)