While it is a great benchmark, that is about 3 year old data. The brotli quality 1 was moved to be quality 2, and two new levels have been added. Everything has been sped up and a few levels (possibly 5-10) have got a ~5 % density boost from improved context modeling. Level 10 has been added (about 2-3x faster than level 11) -- in squash benchmark you still see the initial behavior where level 10 copied level 11 performance.