Philadelphia millennials have been criticized for years for not turning out to vote.

But in the city's May primary, they were the only age group that went to the polls at a higher rate than in the 2014 gubernatorial primary. Every other generation's turnout decreased in that period.

This marks the third consecutive election that saw millennial turnout swell in Philly.

"The numbers are remarkable, that this is the third time in a row that this has happened," said City Commissioner Al Schmidt.

Voter turnout shot up 29 percent among those between the ages of 18 and 34, according to data released by Schmidt's office.

For those aged 35 to 49, participation dropped by 5 percent. It fell 21 percent for voters between the ages of 50 and 64, and sunk 12 percent for those aged 65 and up.

Those percentage changes were calculated by the raw number of voters in each age cohort. A total of 27,749 people between the ages of 18 and 34 voted in May, compared to 21,481 in the 2014 primary. For the sake of comparison, 52,152 voters aged 50 to 64 went to the polls in May, compared to 66,329 four years ago.

"That's the generation that is more energized by Trump," Larry Ceisler, a longtime political observer working in public relations, said of millennials. "It's an expression of community engagement."

As good as the data sound at first blush for millennials, the generation still has the lowest overall voter turnout in the city. It was only 8 percent this May, compared with  7 percent in 2014, according to the City Commissioner's Office.

However, Schmidt said that millennials' voter rolls were likely more falsely inflated than other generations due to the transient nature of young people. When a college student registers to vote in the city and moves out of town four years later, the name is not immediately removed from the books.

Voter turnout was 13 percent for those aged 35 to 49 this year, compared with 15 percent in 2014; and 22 percent for those aged 50 to 64 in May, compared with 28 percent in 2014. Those aged 65 and up came out at a rate of 31 percent last month, a drop from 37 percent in 2014.

Political observers said there was likely a surge in millennial turnout this year because of hotly contested congressional, state House, and committee person races in South Philly and the River Wards.

But why did other generations come out at lower rates than they did 2014? Insiders noted that this year's gubernatorial and U.S. Senate primaries among Democrats were not competitive, perhaps causing less participation. The Pennsylvania governor's race in 2014 featured four candidates.

"Younger voters bucked that trend," Schmidt said.

The areas that saw the biggest boost in millennial turnout were located in Center City as well as rapidly gentrifying areas in South Philly, West Philly, and the River Wards.

Schmidt said on Twitter that "millennial turnout led to these wards having the highest increase in overall turnout" in the primary.