In summary California turnout topped 37 percent in the June primary—but there were wide variations that help explain the oversized power of certain slices of the electorate.

Give yourself a round of applause, California. For a decade, voter participation during midterm primary elections has been slipping down and down. Last time around, in 2014, the state hit an all time low for voter apathy: only one-in-four registered voters bothered to participate.

But this June, we broke the trend. With all ballots counted (finally), a little over 37 percent of those registered to do so got out to vote. (The Secretary of State’s office has a few more days to finalize the numbers.)

Granted, 37 percent might not seem like a triumph of civic participation. But it’s all relative. Getting voters to turn out during off-year elections, when a presidential candidate isn’t on the ballot, has always been a tough sell. Doubly so during primaries—which many voters evidently consider a skippable dry run before the main event in November. This year’s participation rate marks a ten-year high for midterm primaries.

Why the increase? Was it enthusiasm about the gubernatorial standoff between Lt. Gov. Gavin Newsom and Republican John Cox? Excitement about the first viable political independent running for statewide office, in Steve Poizner? Were water conservationists inspired to turnout in mass to support Prop 72, which changed the way that rainwater collection systems are taxed?

Probably not, said David McCuan, a political scientist at Sonoma State University.

Instead, the Trump factor loomed large.

“This particular ballot was not all that sexy,” he said. “The reason for the higher turnout is because of what’s going on in Washington D.C., not what’s happening in California.”

That’s largely borne out by the numbers. Some of the biggest increases in turnout relative to the 2014 midterm primary were in areas with the most competitive congressional races. Orange County as a whole saw a 19 percentage point increase in turnout

Zoom in to the level of Assembly district and the two areas that saw that biggest bump hug the coast between Dana Point and northern San Diego County. That’s home to two congressional seats that Democrats hope to flip this November. Prior to election day, it was ground zero of millions of dollars in advertising and get out the vote efforts. Both districts saw turnout spikes of over 20 points.

That surge in voter enthusiasm “was a little bit of a surprise, but not unexpected,” said Orange County Registrar of Voters Neal Kelley.

Local factors did play a role in some cases. San Francisco, for example, also saw a significant turnout increase. There weren’t any competitive congressional races there. But there was a nail-biter mayoral election that drew national headlines.

Despite the higher than expected turnout, the composition of the electorate may not have changed much. In California, voters tend to skew older, whiter, and more affluent—especially in midterm elections—and there isn’t much evidence thus far that changed this year.

What the data shows: Districts with higher rates of poverty or with a higher population of people who do not speak English very well tended to vote less. Districts where more residents identified as white and non-Latino tended to vote more. Those stats describe districts, not individuals—there are, of course, exceptions.