No we don't. Tesla likes to compare their deaths per mile to the national average. The problem is that their autopilot is not fit to drive everywhere or in all conditions that go into that average. There is no data to support that autopilot is safer overall. It may not even be safer in highway conditions given that we've seen it broadside a semi and now deviate from the lane into a barrier - both in normal to good conditions.
And really, driving conditions are responsible for a relatively small percentage of vehicle fatalities. Most often it's people doing really dumb things like driving 100+ MPH.
The only thing we actually know is these cars are safer on average than similar cars without these systems. That's not looking at how much they are used, just the existence of said safety system and likely relates to them being used when the drivers are extremely drunk or tired which are both extremely dangerous independent of weather conditions.
The US just mandated all new cars have backup cameras, but it seems like mandating AEB would make a bigger difference.
What do you know that the rest of us don't? The ones statistics I've seen on anyone's self-driving cars so far would barely support a hypothesis that they are as capable as an average driver in an average car while operating under highly favourable conditions.
It's not a question of zero deaths, it's a question of reducing the number which means you need to look beyond individual events. Remember the ~90 people who died yesterday from a US car accident without making the news are far more important than a few individuals.