Voter turnout for presidential primaries is usually low. Could 2016 be different?

If past elections are any guide, turnout for next week's presidential primary may be underwhelming in Los Angeles County, even as a heated Democratic campaign enters its last lap in California.

In 2012, when Mitt Romney had already wrapped up the GOP nomination and Barack Obama ran unopposed in his own party, just 21.8 percent of L.A. county voters showed up to the polls. That marked a new low for county participation.

Turnout in presidential primaries has been stuck below 50 percent in most years, ever since the 1984 primary came in at 49.3 percent. It fell below 40 percent for the first time in 1996.

Turnout in midterm elections, when presidential candidates aren't on the ballot, is even worse. It fell to just 17.1 percent in 2014, the lowest showing for a midterm or presidential election in L.A. county since at least the 1940s.

Is there hope for 2016?

Recent history provides one bright spot: 2008, when primary turnout in the county hit 55.3 percent. That year Obama energized many young and first-time voters while fending off a primary challenge from former Sen. Hillary Clinton late into the campaign. Clinton carried the state with 2.6 million votes to Obama's 2.2 million.

This time around, it's Clinton battling Sen. Bernie Sanders. Sanders has pledged to continue his campaign through the California primary, which will keep a spotlight on the state.

"People tend to go to the polls because they're excited and people tend to be excited because they either feel really strongly or they know their vote can make a difference," said Jessica Levinson, a professor at Loyola Law School. "I think in this race, to a certain extent, neither one of those factors are present," she added, due to Clinton's delegate lead and a GOP contest that's effectively over.

Levinson said this primary's turnout could outpace 2012, but she wasn't holding her breath.

Still, voter registration numbers have been strong in the county, especially among young Angelenos.

And one early sign for turnout is positive. "Early voting numbers have dramatically increased since 2012," said Mike Sanchez, a spokesman with the Los Angeles Registrar-Recorder/County Clerk's office. Some 1,705 people have cast early votes at the clerk's office in Norwalk as of Tuesday.

The early vote totals represent a small number of ballots cast, but the number is triple other recent presidential primaries. The figures from the same period in 2012 and 2008 were 583 and 586 votes, respectively.

Turnout improves in general election

Turnout typically improves dramatically for the general election. In fact, only once in the past 75 years has turnout fallen from the midterm to the general in the county. That was in 1978, which was not a presidential election year.

A decent showing in the June 7 primary could presage an improvement in turnout this November. In the chart above, higher primary turnouts often accompany higher general election turnouts. In the 2008 general election, nearly 82 percent of L.A. county voters showed up to the polls.

The county hadn't seen such high voter turnout since the 1968 presidential election, when Richard Nixon carried his home state of California.

This data does not include municipal elections, such as the notoriously low turnout for the 2013 Los Angeles mayoral race.

Los Angeles is the nation's most populous county, with just over 10 million residents.

Registered voters — and their votes — reflect only a certain slice of those residents. In May, the registrar estimated that 4.8 million Angelenos were registered to vote. That's out of 6.1 million eligible voters.

Levinson said that low turnout is a cause for concern. "Low voter turnout really translates into elected officials who are picked by a quote unquote voting class," she said.

The Public Policy Institute of California released a report in March pointing to a growing gap between the "haves" who vote and "have nots" who don't. The state's likely voters skew toward those who are older, white, affluent and college-educated, according to the report, while nonvoters tend to be younger, Latino, and renters with less college education.