It is 1 million terabytes or 1 billion gigabytes.
Forecasts from Cisco
The current Visual Networking Index forecast projects global IP traffic to nearly triple from 2013 to 2018. Overall IP traffic is expected to grow to 132 exabytes per month by 2018, up from 51 exabytes per month in 2013, a CAGR of 21 percent (Figure 1).
Figure 2. Global Devices and Connections Growth