Massachusetts' first experiment in early voting ends Friday. 

The most recent data available, which did not include the last two days of early voting, showed a turnout of roughly 800,000 people statewide—about 17 percent of registered voters, and just under one-quarter of the total percentage of registered voters who turned out in the last presidential election in 2012. 

What do these statistics mean? It's somewhere between difficult and impossible to know: Because 2016 marked the first year of early voting, there exists no data with which to compare the turnout so far. 

And because the Secretary of Commonwealth, which oversees elections in the state, has declined to provide any details but the total statewide turnout so far, it's difficult to know where Massachusetts residents are casting ballots more or less in early voting.   

But we can begin to compare how early voter turnout differs between geographies for which there is data. 

In Boston, where over 33,000 voters have already cast ballots in early voting, turnout has varied, as a percentage of total turnout in 2012, a great deal.

The map below shows early voting turnout by Boston voting ward as a percentage of total turnout in 2012.

The map shows a lot of variation.

In some wards—those in Charlestown, the North End, Downtown, and Back Bay—early voting turned out as much as 20 percent or more of the number of votes cast in the November 2012 presidential election. 

In other parts of the city, early voting has turned out less than 10 percent of votes cast in that election. Early voter turnout was lowest (again: as a percentage of votes cast in 2012) in the area of West Roxbury.