The 2024 presidential election was decided by around 2 million votes. More than 18 million registered voters — 10% of all registered voters — didn’t vote.

Why did so many Americans pass on this civic involvement? For 20% of them, it was simply lack of interest, according to Census Bureau data. Another 18% were too busy, while 15% didn’t like the candidates or issues on the ballot. Illness or disability kept another 12% of them from the polls, 7% were out of town, and 4% just forgot.

Increasingly, people who don’t vote say they just don’t have any interest. In 2004, 11% of registered voters who didn’t cast ballots cited disinterest, nine percentage points lower than 2024’s 20%. Disinterest became the top reason for not voting as of 2020.

More registered voters also eschewed the 2024 election because they didn’t like the candidates or issues. Candidate dislike was the primary reason for 10% in 2004 and peaked at 25% in 2016 — when Donald Trump and Hillary Clinton were the major-party presidential candidates — before receding to 15% in 2024.

While more and more voters struggled with interest, fewer and fewer struggled with access. The percentage of people reporting registration problems as their primary reason for not voting fell from 7% to 4%, and the share citing illness or disability decreased from 15% to 12%. Inconvenient polling places, out-of-town trips, conflicting schedules, and weather were also less common in 2024 than in past elections.

Midterm elections get lower turnout than presidential election years. Some 37 million registered voters didn’t vote in the 2022 midterm, more than two times the total who sat out in 2024.

During the last three midterms, registered voters who didn’t vote were less likely to attribute abstention to disliking the candidates or issues — just 6% listed that as their primary reason in 2022, compared to 15% in 2024. Midterm abstainers were most likely to say they couldn’t find the time: 27% of 2022 non-voters cited time compared to 18% in 2024.

Without a presidential race commanding headlines, more voters might also be altogether unaware, too. In 2022, 8% of registered voters who didn’t vote forgot to vote; during the 2024 presidential election, that share was just 4%.

Personal circumstances can also impact someone’s decision or ability to vote. Age can play a factor — in 2024, 12% of all registered voters who didn’t vote cited illness or disability, but 35% of registered non-voters age 65 and older reported that as their primary reason. Young adults between 18 and 24 were more likely to be out of town than other age groups. Adults between 45 and 64 were the most likely to not care for the candidates or issues.

Recent moves might add some complications — nearly 10% of non-voters who had been at their current residence for less than a year cited registration problems. They were also more likely to be out of town or too busy or to forget.

Educational attainment can also play a role. College-educated voters were less likely to be uninterested but more likely to dislike the candidates and issues.

And there are regional differences. The West sticks out for its high level of disinterest. Despite above-average overall voter turnout, over a quarter of Western non-voters were uninterested (27%), while another 7% forgot.