(Harrisburg) -- The Pennsylvania Department of State is touting that only one percent of eligible voters in the commonwealth do not have the government-issued photo identification they would need, if there were a law requiring all voters to show such ID at the polls. But, that figure may not be above reproach. The Department of State came to its conclusion by using data from PennDOT, which issues drivers licenses and non-driver photo ID. PennDOT provided the number of IDs it has for all Pennsylvanians who are 18 or older. Checked against a national survey of eligible voters, it would appear that only one percent of eligible voters in Pennsylvania don't have ID. But Jan McKnight of PennDOT, says the Department’s number doesn’t pertain ONLY to eligible voters. "So, is it possible that the number of people with IDs from PennDOT is not restricted to the number of people who are eligible to vote?" she asked. "The answer is yes." So, the number of eligible voters in the commonwealth without the ID they would need under a state proposal to require voter ID at the polls could be bigger than one percent. A Department of State spokesman concedes as much, but says the agency believes PennDOT’s numbers are generally reliable. The American Civil Liberties Union of Pennsylvania says it’s important to know the actual number because it could mean thousands who are poor, elderly, and disabled would need to get proper ID if it were a ballot box requirement.