To understand the scale of the hacking attempts against election systems in the 2016 presidential election, consider South Carolina.

On Election Day alone, there were nearly 150,000 attempts to penetrate the state’s voter-registration system, according to a postelection report by the South Carolina State Election Commission.

And South Carolina wasn’t even a competitive state. If hackers were that persistent against a state that President Donald Trump won comfortably, with 54.9% of the vote, it suggests they may have targeted political swing states even more.

In harder-fought Illinois, for instance, hackers were hitting the State Board of Elections “5 times per second, 24 hours per day” from late June until Aug. 12, 2016, when the attacks ceased for unknown reasons, according to an Aug. 26, 2016, report by the state’s computer staff. Hackers ultimately accessed approximately 90,000 voter records, the State Board of Elections said.

Unlike in Illinois, South Carolina didn’t see evidence that any attempted penetration succeeded, said Chris Whitmire, the State Election Commission’s director of public information and training, last week. Most of the attempted intrusions in that state likely came from automated computer bots, not thousands of individual hackers.