Earlier this month, the Justice Department announced the arrest of Ron Hansen, a former Defense Intelligence Agency officer. Hansen is accused of receiving at least $800,000 from Chinese sources in exchange for information he learned from “military and intelligence conferences in the U.S.” and for sensitive technology that the U.S. government had banned from being shared with China.

Hansen is the fourth former intelligence officer — along with Jerry Chun Shing Lee, Joshua Schulte and Kevin Mallory — arrested for espionage or attempted espionage in just the last year. But one part of his story sets him apart: Hansen’s payoff — at least $800,000 — is more than the vast majority of people arrested for spying over the past few decades were paid.

Of course, we’re talking about spying here, so there’s only so much we know about these cases — even the spies who get caught are pretty good at keeping secrets, and the people who catch them are even better. But we can get at least a rough overview of how much spies get paid using two sources: the Defense Personnel Security Research Center’s research into espionage from 1975 to 2008, and its report from last year updating the data to 2015. For cases since 2015, we can use Justice Department press releases.

The data is incomplete, of course — it can’t tell us anything about any spies who weren’t caught or whose payout information was never made public — but all told, I identified more than 100 people who were arrested for spying or similar offenses since 1975 and for whom we can estimate how much they were paid. I then adjusted those income estimates to 2018 dollars, using the year the person was arrested to approximate the year that the payoff was made. It’s an imperfect method, especially for someone like former FBI Special Agent Robert Hanssen, who was arrested in 2001 but likely earned most of his money between 1985 and 1991. But people committing espionage tend not to keep meticulous details of their illicit income, so payment details are, for the most part, best guesses made from the publicly available data.

In any case (caveats aside), what does the data show? There was very little financial gain for the vast majority of people arrested for spying in the cases for which we have payoff data. Most people in our data set didn’t sell secrets so much as give them away: 56 percent got no known compensation for their actions. Another 9 percent were paid less than $12,000, not even enough for the average used car.

Some people — such as Cuban spy Ana Montes — spied for ideological reasons and may have refused payment out of principle. Most of those who weren’t paid, though, were intercepted before they could do real damage — such as Brian Regan, an officer from the National Reconnaissance Office who intended to sell secrets to China, Iraq and Libya for $13 million but was arrested before he could carry out his plan.

Only four U.S. spies are thought to have been paid at least $1 million over their careers: CIA officers Aldrich Ames and Larry Wu-Tai Chin, Army officer Clyde Conrad and Navy officer John Walker. So Hansen’s alleged haul of $800,000 would place him near the top of the list in terms of income derived from passing secrets.

Unsurprisingly, most people arrested for espionage or similar crimes receive lengthy prison sentences regardless of whether they’ve earned lots of money — which they usually haven’t. Ames, Conrad, Hanssen and Walker all received life sentences, while Wu-Tai Chin died by suicide prior to sentencing. Regan and National Guardsman Ryan Anderson similarly received life sentences for unsuccessfully trying to pass secrets to Iraq and Libya (Regan) and al-Qaida (Anderson). In terms of its risk-reward calculation, espionage doesn’t seem like a good bet:

Of course, there are a few limitations to looking at spy data like this.

First and foremost, we can only analyze the spies we know about. There are undoubtedly many former and active spies out there that we may not know about for decades — if at all. The National Security Agency, for example, lists the code names of several assets discovered through VENONA — a Cold War project that aimed to decrypt Soviet cables sent in the 1940s — as either unidentified or having been identified only decades after their spying ended. One such asset was a woman code named “Tina” who the Soviets claimed in 1945 had made a “valuable contribution” to their efforts to steal the atom bomb, and it wasn’t until 1992 that British authorities learned she had been a secretary named Melita Norwood.

Another challenge is that it’s impossible to calculate any payments received by the handful of intelligence professionals who defected from the U.S. over the years. Edward Lee Howard evaded FBI surveillance in 1985 and made it to the Soviet Union after being fired from the CIA. Air Force officer Jeffrey Carney defected to East Germany in 1985, and NSA officers William Martin and Bernon Mitchell fled to Moscow in 1960. There’s no way of accurately gauging how much money or valuables those defectors may have received from their new host countries.

Finally, people who committed espionage on behalf of the U.S. may have made as much or more than even the $2.5 million (over $4 million in 2018 dollars) that Ames was allegedly paid by Russia. One former KGB officer was allegedly paid at least $7 million for a file with Hanssen’s fingerprints and a voice recording of him talking with the KGB, according to a book by David Wise.

And then there’s the case of “Asset X,” who led the CIA to Khalid Sheikh Mohammed, the mastermind of the 9/11 attacks, according to a Senate Select Committee on Intelligence report released in 2014. The information that Asset X gave the U.S. government would have qualified him to claim much or all of the $25 million reward for Mohammed’s capture, and indeed Asset X’s case officer used the reward to motivate the asset to find Mohammed.

But Asset X is more the exception than the rule. Mallory, one of the four U.S. intelligence officers arrested in the last year, was found guilty in early June on charges including selling secrets to China for $25,000. During his trial, Mallory’s attorney argued that, “No one sells national defense information for $25,000. That is pocket change.”

As the evidence shows, however, many people have traded classified information for little more than pocket lint.

Note: Jeff Asher is a former CIA analyst.