Just 71% of voting-age U.S. citizens are registered to vote, and an even smaller share actually makes it to the voting booth on election day. In the 2012 presidential election, 61.8% of eligible U.S. residents went to the polls. The nation’s voter turnout rate trails rates in most developed nations where voter turnout rates tend to be at least 80%.

24/7 Wall St. reviewed average voter turnout rates over the past four presidential election cycles in every state in the nation. Voter participation ranged from approximately three-quarters of eligible Minnesota residents, the highest nationwide, to half of potential voters in Hawaii, the lowest voter turnout rate in the country.

According to Elaine Kamarck, senior fellow at the Brookings Institution, there are two primary predictors of voter turnout. First, the more competitive a particular political contest is, the greater the turnout tends to be. “[If] everybody thinks their vote matters, you get a higher turnout,” Kamarck said. This explains why voter turnout is lower in elections in which candidates run unopposed, as well as why voter turnout rates during primary elections fall over time as candidates generate momentum and it becomes clear who the nominee will ultimately be.

Click here to see voter turnout in each state.

Kamarck explained that voter turnout is higher in competitive states due to another, related variable. States such as Iowa and New Hampshire, which have heated primary races, also tend to have high voter turnout during presidential elections. “The intense amount of politicking [in these states] has meant that they tend to go back and forth even in the presidential election because they tend to be states candidates campaign in,” Kamarck said.

The electoral college system means votes in some states are weighted more than in others. Compared to Texas or California, for example, a single electoral vote in Wyoming is earned with far fewer individual votes. “A vote in Rhode Island, Wyoming, Delaware, all the small states, is much more valuable than your vote is in California,” Kamarck said.

While voting in these smaller states may matter more, the larger weight has not necessarily resulted in higher turnout rates. The average voter turnout rates in Wyoming, Delaware, and Rhode Island — at 63.2%, 66.6%, and 64.4%, respectively — were only slightly higher than or just in line with the national average of 62.3%. That is likely because each of these three states are not especially competitive. Delaware and Rhode Island reliably vote for a Democrat, and a majority of Wyoming voters have supported the Republican candidate in all but eight presidential elections since 1892.

After competitiveness, the strongest predictor of voter turnout is the level of education of area residents, which in turn drives up incomes for participating members of the electorate. While states with above average college attainment rates do not necessarily have above average voter turnout rates, college-educated state residents in every state are more likely to participate in presidential elections than their less-educated peers in every state without exception.

Other democracies around the world typically hold elections on the weekend or declare election day a national holiday. By contrast, presidential elections in the United States are held on Tuesdays, during the work day. Largely because of how elections are held in the United States, individuals living in poverty are far less likely to vote than higher income individuals — not because of low education but rather, at this extreme low end of the income spectrum, due to lack of flexibility in the workplace.

Largely because of how elections are held in the United States, individuals living in poverty are far less likely to vote than higher income individuals due to lack of flexibility in the workplace. “People who are paid on an hourly basis can’t take off time to vote, so often they don’t vote,” Kamarck said. Indeed the most prevalent reason among voters for not going to the polls was conflicting work or school schedules.

To identify the states with the highest and lowest voter turnout rates,24/7 Wall St. reviewed the average percentage in each state of voting-age citizens who cast a ballot in the past four presidential elections, as well as the percentage of votes for the Republican and Democratic nominees in each of these races. All voter turnout data came from the Current Population Survey (CPS), conducted by the U.S. Census Bureau every month. Also from the CPS, we looked at reasons people cited for not voting, as well as average weekly wages per state and nationwide. The percentage of adults who have at least a bachelor’s degree and poverty rates came from the U.S Census Bureau’s 2014 American Community Survey (ACS). Unemployment rates came from the Bureau of Labor Statistics (BLS).

These are the states with the highest (and lowest) voter turnout.