In Apple's 2014 EEO-1 they distinguish between professionals and technicians. Professionals are 1.7% black and technicians are 11.3% black. I assume both of these are lumped into a single "tech workforce" number.
Wow, thank you sir. Note that 1.7% is roughly the same percentage that Google, Facebook, and Twitter have according to OP. I hope OP sees this and reevaluates his position now that Apple's diversity numbers no longer appear to be 4x higher than the rest.