When a major U.S. city first has 10% of its taxis be autonomous vehicles

Clarifications: This question resolves on the first calendar date on which at least one of the 30 largest U.S. cities has at least 10% of its active taxis in commercial operation that are autonomous vehicles without a driver. The active taxis in commercial operation accounts for human licence-driven taxis or private hire drivers (Uber, Lyft, etc) in that city. 'Active robotaxis in operation' means vehicles available to the public for paid rides or otherwise operating as part of a commercial robotaxi service; test vehicles, employee-only shuttles, and vehicles not available for public rides do not count. The comparison is city-specific and based on the best available public counts for that city.