Ask HN: NSA SSL Private Keys?

So we know that the NSA are capturing the majority of internet traffic passing through the USA, currently it's a bit more vage on how much access they have to the data/servers of Facebook, Google, Twitter etc...

And a high percentage of the internet traffic these days it SSL encrypted, especially the more interesting traffic.

So what's the chance that the NSA have Google's, Facebook's Private SSL keys? and their actually decrypting the mirrored internet traffic that we know their capturing?