Yeah and 6+ was < 10%. This list definitely seems biased toward the higher levels. 41 Staff SWEs and only 60 Senior SWEs is a crazy ratio. Consistent with the rumor that they targeted high comp packages.
Terminal level generally indicates a glass ceiling that most folks can't rise above. Senior and Staff are generally terminal levels for the rest of the industry.
It's hard to gauge whether the layoffs at the senior level are large or small.