HARRISBURG, Pa. (AP) — Pennsylvania election officials say noncitizen immigrants may have cast 544 ballots illegally out of more than 93 million ballots in elections spanning 18 years in the state.

Department of State official Jonathan Marks told the state House State Government Committee on Wednesday that the agency conducted an analysis covering 35 primary and general elections from 2000 through 2017.

The number of ballots potentially cast by the noncitizen immigrants is one in every 172,000.

The department says those votes were apparently cast by noncitizen immigrants who later reported themselves as having mistakenly registered, though it also said it cannot guarantee the figure is accurate yet.

The state has previously acknowledged that noncitizen immigrants can inadvertently register to vote because of a glitch in the design of Pennsylvania's electronic driver's licensing system.