State and local governments in Iowa racked up an additional $462 million in debt in the last fiscal year — the biggest annual percentage increase since 2013, a new state treasury report shows.

All told, Iowa governments now owe almost $15.9 billion, a 3 percent increase since 2016.

DATABASE:Outstanding debt for Iowa's state and local governments

But State Treasurer Michael Fitzgerald said those numbers might not be as alarming as they sound because Iowa governments have taken advantage of low interest rates to tackle deferred infrastructure projects.

“If you think we’re never going to have to improve our infrastructure, that’s unrealistic,” Fitzgerald said. “We should maintain our infrastructure and how we run government, and we just haven’t always done that.”

Pressure has long been placed on governments across the nation to address deferred maintenance, particularly after highly publicized events such as the 2007 interstate bridge collapse in downtown Minneapolis that killed 13 people and injured 145 others.

Those long-term projects such as new bridges typically are too expensive to have taxpayers pay for them up front.

​​​​​​Iowa is ranked among the 10 lowest debt levels in the nation compared with its “gross state product," according to The States Project, which is part of Harvard University’s Institute of Politics at the Kennedy School.

​​​​​​The national conversation about debt and concerns that it saddles taxpayers far into the future is ongoing. The U.S. government has nearly $20 trillion of debt, the most of 43 countries analyzed in a report published in September by the Pew Research Center.

The Register previously reviewed Iowa’s highest per-capita debt cities, schools and counties for the fiscal year that ended in June of 2013 and found some governments are holding the equivalent of more than $10,000 in debt for each of its citizens.

The city with the highest per-capita debt in 2013 was Coralville, which in 2016 restructured about $60 million in debt as part of a plan to obtain better interest rates.

State records show that Coralville had almost $273 million in debt in the fiscal year that ended June 30, a $5.3 million drop from 2013.

The city in 2013 hired a consultant who laid out a plan to cut the city’s debt in half by 2024.

Coralville has widened and improved several major roads that lead into the city and is wrapping up more than $70 million of projects following floods from almost a decade ago, Coralville City Administrator Kelly Hayworth said.

The improvements are necessary to maintain growth, he said.

“It’s been a major goal of our council and mayor to continue the effort to improve in that (debt management) area,” Hayworth said. “We’re making progress.”

The University of Iowa had the highest outstanding debt of any Iowa government, with $1.12 billion, according to the report.

Des Moines led all Iowa cities with $460 million in debt.