[ksec]

Anywhere from 5-15% if I remember correctly depending on source material. I was at one point thinking this would make JPEG-XL and AV1F moot because all of a sudden JPEG became good enough again. But the Author of JPEG-XL suggest there is still so much JPEG-XL encoder can do to further optimise bit / quality especially in the bpp below 1.0 range.