Where do you get that? Seems like from the most recent recall 4%ish was more accurate when you add the reported failures noted in the recalls together, and that was what had failed pre recall replacement. Toyota also said "good" engines torn down also showed signs of debris/damage that would lead to failure. They did not say how many they tore down or the % of those with damage, so there is now way to extrapolate what % of those on the road are going to fail. Could be another percent or two, or could be 50%.
The % appears to be much higher than 1%, and that # will grow.
It does seem like fewer 26s are failing as earlier years after being on the road for half a year, but time will tell...