PHILADELPHIA (CBS) — Robocalls are frustrating. Now, a new report finds they’re happening at an alarming rate, even though millions of numbers are on the “Do Not Call” list.

In fact, those annoying calls have now reached a record level of 18 billion, meaning Americans fielded 76 percent more robocalls than they did in 2016, according to a new analysis by Hiya, a robocall blocking service.

This is puzzling for many, considering the Federal Trade Commission’s Do Not Call Registry has grown by nearly 4 million phone numbers over the course of the past year.

The registry now has 230 million phone numbers on it, up from 226 million a year ago. However, complaints about unwanted telemarketing calls soared 34 percent during the year, the agency said. The vast majority of those unwanted calls were made by computers — robocalls. Both Hiya and the FTC issued year-end reports this week.

And although the “Do Not Call” list is legitimate, it only blocks legal calls, while many of the ones people receive are illegal.

Experts say if you don’t recognize a number, don’t pick up.