Waymos crash less than human drivers

> Using human crash data, Waymo estimated that human drivers on the same roads would get into 78 crashes serious enough to trigger an airbag. By comparison, Waymo’s driverless vehicles only got into 13 airbag crashes. That represents an 83 percent reduction in airbag crashes relative to typical human drivers.

> This is slightly worse than last September, when Waymo estimated an 84 percent reduction in airbag crashes over Waymo’s first 21 million miles.

nitpick: Is it really slightly worse, or is it "effectively unchanged" with such sparse numbers? At a glance, the sentence is misleading even though it might be correct on paper. Could've said: "This improvement holds from last September..."

Of course it's not worse, these numbers have huge error bars. Statistically the two statistics are not significantly different. But trying to explain that to most people with no knowledge of statistics is tough.