SAN FRANCISCO — Google co-founder Sergey Brin on Wednesday defended his company's policy of not releasing accident reports for its self-driving cars, saying the Internet giant is trying to protect the privacy of the human drivers who caused the collisions.

Even if the names were redacted from the records, Brin said, the reports would just confirm a summary posted online three weeks ago.

The number of accidents rose to 12 in the past week after a self-driving car was rear-ended, Brin said.

Brin reiterated that Google's self-driving cars have never been at fault in the accidents, although in one instance a Google employee was driving the car when it collided with another vehicle.

Though nothing "can be perfect," Brin said, "our goal is to beat human drivers."

Brin made the remarks at Google's annual shareholder meeting under questioning from Consumer Watchdog's John Simpson.