NBC’s Olympics nightmare has all but come true: Prime-time viewership for Rio is down 17% from the London Games in 2012.

At a conference in June, NBC CEO Steve Burke explained what would constitute an Olympics "nightmare," Bloomberg reports. "We wake up someday and the ratings are down 20%," he said. "If that happens, my prediction would be that millennials had been in a Facebook bubble or a Snapchat bubble and the Olympics have come, and they didn't know it."

That nightmare is basically here, as the Olympics saw a sharp viewership dip for the first time since 2000. Among 18- to 49-year-olds, the damage is even greater than 20%, sitting at a 25% drop-off, according to Bloomberg Intelligence.

That's bad news for NBC, which paid $12 billion to lock up the rights to the Olympics through 2032.

There is, however, a slight silver lining.

About 24% more people have streamed the Rio Olympics through NBC's app and website than streamed the London Games over the same period. NBC told Bloomberg that 78 million unique users had streamed the games through Tuesday. And NBC has actually been able to charge 50% higher ad rates for internet ads than for those on TV because of the younger audience, NBC Sports chairman Mark Lazarus told Bloomberg.

But that good news should be put into harsh perspective: 98% of people still watch the Olympics on TV, the medium that has seen its audience plummet.