American workers steal from their employers — a lot.

Employees in the U.S. steal from their employers at significantly higher rates than workers in other countries, according to The Global Retail Theft Barometer released this month by Checkpoint Systems. While in most countries shoplifting makes up the bulk of shrinkage, in the U.S. the bulk of shrinkage is due to employees stealing from their employers. In layman’s terms, shrinkage is the difference between the revenue businesses should have received and the revenue they did receive, and the difference is due in large part to losses from shoplifting, employee theft and vendor/supplier fraud. Indeed, employee theft is responsible for 45% (up from 43% last year) of shrinkage in the U.S. (vs. 36% from shoplifting). Globally, it’s just 39% from employee theft (vs. 38% from shoplifting).

While experts at The Global Retail Theft Barometer say it’s not clear why employee theft is so high in the U.S. — at least compared with other countries — they do have information on how these workers steal from their employers. Most of it happens during checkout/the point of sale “when an associate purposely manipulates a transaction for the benefit of themselves or someone else,” says Ernie Deyle, the study co-author and an industry consultant, who also serves as lead for Crisis Management, Safety & Enterprise Resiliency at Sears Holding Company. For example, workers may issue refunds, discounts or voids at the register when they shouldn’t, or cancel transactions, modify prices or say someone used a coupon when they didn’t.

And that all adds up: Employee theft cost U.S. retailers $16.6 billion in the past year-- that’s $3 billion more than shoplifting cost them and about $10 billion more than vendor and supplier fraud and administrative and non-crime losses cost them combined. Some of the reasons that employees steal include ineffective pre-employment screening, less employee supervision and easy sale of stolen merchandise, the report reveals.

Employee theft at certain kinds of stores in this country is more prominent than at others. Department stores, for example, experience a very high rate of employee theft as a percentage of total shrinkage, while more niche retailers like home improvement and gardening stores do not.

4 types of stores that have the worst problems with employee theft

Dishonest employee theft Shoplifting Vendor or supplier fraud Administrative and non-crime losses Department stores 59% 35% 3% 3% Supermarkets and grocery stores 50% 31% 10% 10% Apparel specialty retailers (this includes stores that primarily sell clothing like Gap or Abercrombie) 44% 41% 4% 12% Hypermarkets (a combo of a supermarket and department store) and mass merchandisers (like Target and Walmart) 47% 32% 11% 11%

This story has been updated.