Luckily, you're on a news site where I'm sure this fact has been reported many times.
Opinion. Not fact.
Note that if NSA is doing its job properly, you'll never hear about its successes. So it could be 99.9% successful and fail 0.1% of the time, and you'd still hear about nothing but its failures in the news.
Likewise, of course, for 0.1% success and 99.9% failure.
Which is why any information about the NSA's functionality is an opinion. Even if it's promulgated by Congress, President, NSA head, whatever (since all of them have reasons to lie about it - if you KNOW it's doing it's job well, telling everyone it's not is a GOOD thing, not a bad thing)...