Two years after Apple Inc. dropped Google Maps as its default service on iPhones in favor of its own app, Google had regained only 40% of the mobile traffic it used to have on its mapping service, a Google executive testified in the antitrust trial against the Alphabet Inc. company.

Michael Roszak, Google’s vice president for finance, said Tuesday that the company used the Apple Maps switch as “a data point” when modeling what might happen if the iPhone maker replaced Google’s search engine as the default on Apple’s Safari browser.

In a June 2020 email to his then-supervisor, Roszak shared data on how Apple’s switch affected Google Maps usage on iPhones.

“Almost 2 years later we were at ~40% of the prior peak (and assumed the actual loss was greater since Apple Maps usage was also growing across this time),” Roszak wrote in an email introduced in court. The chart Roszak included in the email that showed Google Maps usage on iPhone was redacted from the public version of the document.

The Justice Department alleges that Google has illegally maintained a monopoly over online search by paying billions of dollars to ensure its search engine is the preselected option, known as the default, on web browsers and smartphones. Google’s largest contract is with Apple, which set Google as the default on Safari in exchange for a share of the revenue that the search engine earns through advertising.

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The exact amount of money Google pays Apple for its default status isn’t public. The Justice Department said in its opening statement that Google paid between $4 billion and $7 billion for the default on Safari in 2020 — a statement that led to an objection by Apple’s lawyers the next day since that is a public estimate and not the actual figure.

Roszak said Tuesday that he wasn’t aware of any data that Google keeps on how many users change the search default on their browser or mobile phone. The Apple Maps example was “one data point we have used” to estimate how iPhone owners might react to a change in the search default, he said.

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