We mailed (another) 62 packages in swing states. Here's where it went well — and didn't.

Heading into election week, the USA TODAY network’s effort to measure mail efficiency showed high rates of on-time delivery in some swing states but continuing signs of problems in others.

Of 62 packages mailed since Oct. 13, 12 took more than the three-day shipping standard set forth by the post office.

Five took a week or more.

Michigan accounted for eight of the late shipments. Florida had two. One in Ohio sent the 19th has yet to arrive.

By contrast, mailings in Pennsylvania, Wisconsin and Nebraska’s second district took no more than two days to arrive at their destination. Eight of the nine Arizona letters arrived with time to spare; one barely missed the goal at four days. The recent mailings provided a larger set of data for those four locales than in previous weeks.

The University of Maryland’s Howard Center for Investigative Journalism is partnering with USA TODAY on the project.

The findings continue to demonstrate just how long delays can last, making it difficult for voters to ensure that mailed ballots will arrive on time. Michigan, Ohio and Florida all showed delays in earlier weeks of the news organization’s mail effort, as well.

Due to the long delays, Michigan Secretary of State Jocelyn Benson suggested voters bypass the mail altogether in the final two weeks before the election.

The importance of speedy deliveries was highlighted again this week, when the U.S. Supreme Court ruled against an effort to allow Wisconsin ballots to count if they arrive past Election Day Nov. 3.

Millions of people are likely to vote by mail this year because of the coronavirus pandemic, and most are registered Democrats.

The postal service reported significant delays this summer after cost-cutting measures were implemented by new Postmaster General Louis DeJoy. DeJoy ordered the dismantling and deactivation of mail sorting machines, barred overtime and required carriers and trucks to start routes at certain times, regardless of whether the mail was ready, resulting in widespread slowdowns.

Many of those efforts were halted by court order.

But a filing in the Washington D.C. District Court showed many postal districts continue to see delays for a large percentage of mailings. Philadelphia was the worst, with less than 60% of first-class packages delivered on time. Detroit had the fourth-worst rate, with 72% meeting the standard.

The mailings by USA TODAY show just how long those delays can last.

The news organization has tracked short-distance delivery times by sending certified mail, which carries a bar code and a tracking number that allow customers to check online each time and location where postal employees log its status.

The longest recent trip was recorded by a letter sent from suburban Detroit. On Oct. 13, it arrived at a distribution center in Pontiac. It finally left the center nine days later, and has yet to arrive at its destination back in Birmingham.

Another long mailing was recorded by a package mailed in Weinland Park, near Ohio State University in Columbus. An envelope mailed from there Oct. 19th continues to make its way to its destination near a postal facility in the northeastern part of town.

A certified envelope mailed from Bradenton, Florida, on Oct. 22 also has not yet arrived.

Contributing, from the USA TODAY Network: Nick Penzenstadler, Danielle Delfin, Gary White, Dak Le, Wade Tatengelo, Erin Mansfield, Carrie Seidman, Mike Stucka, Mark Wert, Kim Bui, Josh Susong, Craig Harris, Teresa Boeckel, Jessica Boehm, Karina Bland, Michael Squires, Wyatt Buchanan, Carrie Waters, Doug Schneider, Renee Hickman, Patrick Marley, Brian Dickerson, Steven Pepple, Kristen Shamus, Christina Hall, Elissa Robinson, Elisha Anderson, Frank Witsil, Chris Ullery, Kevin Dittman, Laura Schulte, Scott Fisher, Alison Dirr, Sarah Hauer. From the Howard Center: Krishnan Vasudevan and Sean Mussenden.

This article originally appeared on USA TODAY: Election 2020: Mail ballots moved quickly in most states. Not these.