The number of robocalls being placed in the U.S. is skyrocketing.

A new survey found 3.36 billion robocalls were placed last month. That's up 34 percent over this time last year.

New York state ranked fifth in the nation for most robocalls in the nation. Nassau County alone received 14.7 million calls last month.

There are robocall-blocking apps that can be added to cellphones. Experts say to make sure your home and mobile number are on the federal do not call list.

Alex Quilici, from YouMail, says most of the illegal or scam robocalls are coming from overseas  and use software to spoof telephone numbers on caller ID. YouMail also tells News 12 Long Island that its research found more robocalls are sent to iPhones than Androids.

Washington lawmakers are working on a bill that would require cell and landline phone companies to provide robocall blocking features for customers.