Just 1% of the vacuum cleaners, immersion blenders and other household products listed on Amazon last year were sold by the retailer, with the rest coming from other merchants who use its platform. And yet 33% of all sales in that category were by Amazon.

Those were among the figures published last week in a little-noticed chart, based on internal Amazon data, that was part of the House Judiciary Committee’s mammoth antitrust report on big tech companies. The data revealed how Amazon manages to grab a hefty slice of sales on its site despite its third-party sellers accounting for nearly all of the listings in most major product categories. Amazon’s competitive relationship with the independent sellers on its site is a key focus of antitrust regulators currently scrutinizing the company in the U.S. and Europe.