This does not count all viewers. And so not their overall influence.
Missing are foreign audiences on their own cable systems, which do not figure in US surveys, but do generate ad revenue, plus online repeats and clips on youtube, social media, etc.
CNN is THE US news service outside the US. Its influence abroad is way greater than one woukd think.
Definitely a reduction in traditional US audience reach, but thats not everything.
Yes, most Canadians use CNN for their outlook on America.