The article is presumably referring to a transfer rate of 2 terabits per second, not 2 terabits of data transferred over the course of 24 hours.
2Tbps for a country of 4.5m people sounds about right.
2Tbps for a country of 4.5m people sounds about right.
If we take New Zealand to be equivalent to the North American average (higher than the European average) of 14.5 GiB/user-month, and apply that to the 2.6 million internet connected people in New Zealand, this equates to an average bandwidth of 14.5 GiB/sec, or around 116 gigabits per second.
The only way you can get close to 2 terabits per second is to assume all of those 2.6 million people use 256 gigabytes of bandwidth per month - and certainly, I don't think that the people in NZ use ten to twenty times as much bandwidth as the other countries in the world [1]. (Other assumptions: 30 days in a month, and all of the 66% internet connected population in NZ uses 14.5 GiB per month)