So a million S9's use 1,400 million Watts of power, or 1.4 GigaWatts of power.
The total annual electric energy generated by humanity is about 24,000 TeraWatt-hours. (wikipedia)
Final improved calc (I also made a mistake in original calc)
1.4 Gwh for miners
2.31 TWh (2310 Gwh) continuous average for Earth
see
https://en.wikipedia.org/wiki/Electric_energy_consumption1.4/2310=0.0006 or 0.06%
maybe if you count less efficient miners, the real number is 50% higher (although I doubt it because old miners like S7produce 3-4 times less than S9) to 0.1%
0.1% is max, with 0.07-0.075% being more realistic.
However, banks consume at least five times more energy:
https://www.bitsonline.com/bitcoin-vs-banks-uses-energy/