Page 68.

"Total onboard waste at hub airports"

As one ton is equals 1.0183242 cubic meters, 18.6 million tones had to be converted to cubic meters.

1 Metric ton = 1000 m3

(Calculation: 18.6*10*6*1000 = 18,600,000,000)

http://convertwizard.com/convert-tons-to-cubic_meters