The 2016 presidential election saw low turnout among young voters—only half of all eligible voters aged 18 to 29 cast ballots, about where turnout has hovered for the past four elections. But for city elections, the younger voter turnout is even worse. According to a new study that looks at 30 mayoral races in 30 cities, the oldest generation of Americans is making pretty much all the local government decisions.

A Portland State University study named “Who Votes for Mayor?” takes a look at who exactly shows up at the polls to determine the fate of their cities. Not only is turnout for local elections very low overall, the median age of voters for local elections is a mind-boggling 57. Overall, retirees are seven times more likely to vote than millennials.

Even more so than national politics, municipal politics is shaped by huge age disparity in who votes. pic.twitter.com/BgchtaAuMZ — Matthew Yglesias (@mattyglesias) January 18, 2017

In about half of the cities featured in the study, millennial voting rates hovered in the single digits. This is partially because this age group is more itinerant overall; many go away to college and move to new cities for jobs. But there was one bright spot— Portland, Oregon—which not only has high overall turnout rates, but also very good young voter turnout. This is because the mayoral election included in the study was timed with the 2012 presidential election—which is a strategy recommended by the study’s authors to boost turnout.

But Portland also has higher turnout than average because of the unique way that voting is conducted: Oregon’s system allows all voters to cast ballots at their convenience by mail over a period of several weeks. (Phil Keisling, one of the authors, oversaw the move to vote-by-mail when he was Oregon’s secretary of state.)

Oregon’s success might offer an interesting idea for boosting turnout elsewhere: publicizing turnout rates, writes Mike Maciag in a piece for Governing magazine. “Where voting takes place over a period of several weeks, as in Oregon, cities could report real-time data showing turnout by neighborhood, age group and other demographics.”

One wonders if a widely shared real-time voter turnout tracker—similar to the daily polling data we saw during the 2016 election—might motivate young, tech-savvy citizens to get out the vote.