I did something similar [1] though not nearly as detailed, whereby as of Sep 2017 I estimated the total hash power to be equivalent to 712,672 S9 miners, which roughly adds up to

  8.584 TWh/year
  8.584 / 109613 = 0.00008 = 0.008%

  (109613 TWh is the annual world consumption number you used)

[1] - Electricity cost of 1 BTC https://grisha.org/blog/2017/09/28/electricity-cost-of-1-bit...

P.S.: I think this is a high estimate, because companies like BitFury have access to much more energy efficient asics which they're keeping secret. We should at least re-calculate this using the new DragonMint miner numbers instead of S9.