How many spies are there anyway? Many Americans were surprised in 2018 by allegations that a Russian woman, Mariia Butina, had infiltrated the National Rifle Association and was having sex with well-placed men, in the hopes of receiving information for Russia. Politico has reported that Russia and China are significantly stepping up their spying operations in Silicon Valley, to extract useful tech knowledge.

I think Americans underestimate the extent of spying in their midst. Because we do not know the number of operating spies, that’s a hard hypothesis to test, but there are a number of reasons to find it plausible.

Our underestimation is partly the fault of movies and television, which give us overly glamorized images of espionage.

Tom Cruise’s Ethan Hunt was described as “hyper-human” in the latest installment in the “Mission: Impossible” franchise, which was the top performer at the box office in July of 2018. We are used to James Bond visiting the British Secret Service technology officer “Q,” and receiving an array of gadgets, such as a specially equipped Aston Martin that can create its own oil slicks. Fewer movies are made about lower-cost, mundane spies, and so Americans are misled. We think of spies as exotic, and so we imagine them as rare rather than commonplace. The TV show “The Americans” also contributed to this false impression.

Furthermore, think about the bureaucratic side of spying. We tend to focus on the cloak and dagger side of the KGB and successor institutions, but they’re also just government agencies trying to boost their budgets and achieve higher status in their home country. In other words, spy agencies play the typical bureaucratic games.

To maintain their status and privileged perch, spy agencies may try to take credit for as many activities as possible. This emphasis of quantity over quality is a typical bureaucratic response to a political system based on imperfect information. It is hard for national leaders to judge how effective their spy agencies are, so the spy agencies want to pass along good numbers, much as a corporation might try to slant its quarterly earnings report.

These incentives encourage spy agencies to maintain arms-length relationships with a large number of potentially connected individuals. They may end up working as part-time or opportunistic spies, but most of the time they hold normal jobs, albeit in sectors that are potentially sensitive. An example would be the large number of Chinese-born individuals who work in the tech sector, some of whom have an open invitation to report useful information back to the spymasters, in return for payments. The spy agency can curry favor by reporting that it has a network of a particular size, operating in many companies and sectors.

In the account of Chinese spying in Silicon Valley, it was noted that the NIMBY movement that restricts construction and the resulting high rental prices are a major problem for the spies there. That too suggests that most spies and potential spies lead a rather ordinary existence; they are not lavishly funded by their home governments. They may simply be working on “spec,” and steal information opportunistically or perhaps never at all. That too is consistent with the number of spies being higher than we might think.

If we look back at American history, whenever foreign spies were caught the reaction of the public was one of surprise or shock. When Ethel and Julius Rosenberg were found to have done nuclear spying for the Soviet Union, the U.S. was caught unprepared. When Jonathan Pollard was caught spying for Israel, that too came as news to many Americans. The McCarthy era in the 1950s seems to be the exceptional period when perhaps a large segment of the American public was overestimating the number of spies in the country and government.

One former American counterintelligence officer estimated that there were about 100,000 foreign agents spying on the U.S., working for about 60 to 80 nations. To put that in perspective, there are about 50,000 coal miners in the U.S., or half the number of foreign spies.

But I wonder if the actual number of foreign spies isn’t larger yet. John Negroponte, former director of national intelligence, admitted in 2006 that the U.S. was deploying about 100,000 spies around the world. Given that the U.S. is the world’s technology and military leader, and yet has a relatively small share of global population, is it so crazy to think the number of people spying on us is larger than that?

Tyler Cowen is a Bloomberg Opinion columnist. He is a professor of economics at George Mason University and writes for the blog Marginal Revolution. His books include “The Complacent Class: The Self-Defeating Quest for the American Dream.”