Approximately what percentage of the state’s voting-age population is registered to vote?

If early voting trends are any indication, a record number of Americans could vote in the 2020 presidential election. As of this writing, more than 100 million early votes have been cast by mail or in person – more than two-thirds of the total number of votes cast in 2016.

We won’t have anything like a definitive assessment of 2020 turnout rates for some time after Nov. 3. But in the 2016 presidential election, nearly 56% of the U.S. voting-age population cast a ballot. That represented a slight uptick from 2012 but was lower than in the record year of 2008, when turnout topped 58% of the voting-age population.

So how does voter turnout in the United States compare with turnout in other countries? That depends very much on which country you’re looking at and which measuring stick you use.

Political scientists often define turnout as votes cast divided by the number of eligible voters. But because eligible-voter estimates are not readily available for many countries, we’re basing our cross-national turnout comparisons on estimates of voting-age population (or VAP), which are more readily available, as well as on registered voters. (Read “How we did this” for details.)

Comparing U.S. national election turnout rates with rates in other countries can yield different results, depending on how turnout is calculated. Political scientists often define turnout as votes cast divided by the estimated number of eligible voters. But eligible-voter estimates are difficult or impossible to find for many nations. So to compare turnout calculations internationally, we’re using two different denominators: total registered voters and estimated voting-age populations, or VAP, because they’re readily available for most countries.

We calculated turnout rates for the most recent national election in each country, except in cases where that election was for a largely ceremonial position or for European Parliament members (turnout is often substantially lower in such elections). Voting-age population turnout is derived from estimates of each country’s VAP by the International Institute for Democracy and Electoral Assistance. Registered-voter turnout is derived from each country’s reported registration data. Because of methodological differences, in some countries IDEA’s VAP estimates are lower than the reported number of registered voters.

In addition to information from IDEA, data is also drawn from the U.S. Census Bureau, the Office of the Clerk of the U.S. House of Representatives, and individual nations’ statistical and election authorities.

Overall, 245.5 million Americans were ages 18 and older in November 2016, about 157.6 million of whom reported being registered to vote, according to Census Bureau estimates. Just over 137.5 million people told the census they voted that year, somewhat higher than the actual number of votes tallied – nearly 136.8 million, according to figures compiled by the Office of the Clerk of the U.S. House of Representatives (which include more than 170,000 blank, spoiled or otherwise null ballots). That sort of overstatement has long been noted by researchers; the comparisons and charts in this analysis use the House Clerk’s figure, along with data from the International Institute for Democracy and Electoral Assistance and individual nations’ statistical and elections authorities.

The 55.7% VAP turnout in 2016 puts the U.S. behind most of its peers in the Organization for Economic Cooperation and Development, most of whose members are highly developed democratic states. Looking at the most recent nationwide election in each OECD nation, the U.S. places 30th out of 35 nations for which data is available.

By international standards, 2016 U.S. voter turnout was low

Pew Research Center

The highest turnout rates among OECD nations were in Turkey (89% of voting-age population), Sweden (82.1%), Australia (80.8%), Belgium (77.9%) and South Korea (77.9%). Switzerland consistently has the lowest turnout in the OECD: In 2019 federal elections, barely 36% of the Swiss voting-age population voted.

One factor behind the consistently high turnout rates in Australia and Belgium may be that they are among the 21 nations around the world, including six in the OECD, with some form of compulsory voting. One canton in Switzerland has compulsory voting as well.

While compulsory-voting laws aren’t always strictly enforced, their presence or absence can have dramatic effects on turnout. In Chile, for example, turnout plunged after the country moved from compulsory to voluntary voting in 2012 and began automatically putting all eligible citizens on the voter rolls. Even though essentially all voting-age citizens were registered to vote in Chile’s 2013 elections, turnout in the presidential race plunged to 42%, versus 87% in 2010 when the compulsory-voting law was still in place. (Turnout rebounded slightly in the 2017 presidential election, to 49% of registered voters.)

Chile’s situation points to yet another complicating factor when comparing turnout rates across countries: the distinction between who’s eligible to vote and who’s actually registered to do so. In many countries, the national government takes the lead in getting people’s names on the rolls – whether by registering them automatically once they become eligible (as in, for example, Sweden or Germany) or by aggressively seeking out and registering eligible voters (as in the UK and Australia). As a result, turnout looks pretty similar regardless of whether you’re looking at voting-age population or registered voters.

In the U.S., by contrast, registration is decentralized and mainly an individual responsibility. And registered voters represent a much smaller share of potential voters in the U.S. than in many other countries. Only about 64% of the U.S. voting-age population (and 70% of voting-age citizens) was registered in 2016, according to the Census Bureau. The U.S. rate is much lower than many other OECD countries: For example, the share of the voting-age population that is registered to vote is 92% in the UK (2019), 93% in Canada (2019), 94% in Sweden (2018) and 99% in Slovakia (2020). Luxembourg also has a low rate (54%), although it represents something of a special case because nearly half of the tiny country’s population is foreign born.

As a consequence, turnout comparisons based only on registered voters may not be very meaningful. For instance, U.S. turnout in 2016 was 86.8% of registered voters, fifth-highest among OECD countries and second-highest among those without compulsory voting. But registered voters in the U.S. are much more of a self-selected group, already more likely to vote because they took the trouble to register themselves.

There are even more ways to calculate turnout. Michael McDonald, a political scientist at the University of Florida who runs the United States Election Project, estimates turnout as a share of the “voting-eligible population” by subtracting noncitizens and ineligible felons from the voting-age population and adding eligible overseas voters. Using those calculations, U.S. turnout improves somewhat, to 60.1% of the 2016 voting-eligible population. However, McDonald doesn’t calculate comparable estimates for other countries.

No matter how they’re measured, U.S. turnout rates have been fairly consistent over the past several decades, despite some election-to-election variation. Since 1976, voting-age turnout has remained within an 8.5 percentage point range – from just under 50% in 1996, when Bill Clinton was reelected, to just over 58% in 2008, when Barack Obama won the White House. However, turnout varies considerably among different racial, ethnic and age groups.

In several other OECD countries, turnout has drifted lower in recent decades. Greece has a compulsory-voting law on the books, though it’s not enforced; turnout there in parliamentary elections fell from 89% in 2000 to 63.5% last year. In Norway’s most recent parliamentary elections, 2017, 70.6% of the voting-age population cast ballots – the lowest turnout rate in at least four decades. And in Slovenia, a burst of enthusiasm followed the country’s independence from Yugoslavia in 1992, when 85% of the voting-age population cast ballots – but turnout has fallen nearly 31 percentage points in two-and-a-half decades of democracy, sinking to 54.6% in 2018.

On the other hand, turnout in recent elections has bumped up in several OECD countries. Canadian turnout in the two most recent parliamentary elections (2015 and 2019) topped 62%, the highest rate since 1993. In Slovakia’s legislative elections this past February, nearly two-thirds (65.4%) of the voting-age population cast ballots, up from 59.4% in 2016. And in Hungary’s 2018 parliamentary elections, nearly 72% of the voting-age population voted, up from 63.3% in 2014.

Note: This is an update of a post originally published May 6, 2015.