Roughly 295,000 Democrats and 78,000 Republican are eligible to vote in Tuesday's primary but it may be the 380,000 voters who are not registered with either party who hold sway in selecting delegates from Rhode Island to the party national conventions in July.

About 59 percent of the voters are age 30 to 64, The Providence Journal learned by analyzing the voter database maintained by the secretary of state's office. Another 21 percent are 65 or older and 20 percent are younger than 30.

The Journal's analysis documented the demographics of Tuesday's electorate, yielding information on the serious side and some decidedly more whimsical.

Among the findings:

— A total of 756,703 people are eligible to vote in an election on Tuesday, though 2,635 of them are members of the Moderate Party, which has no candidate on a ballot. People registered with a party may vote only in their party's primary, while unaffiliated voters may choose any party's primary but cannot vote in more than one.

— Democrats skew oldest, with 24 percent of them 65 and older and only 16 percent younger than 30. Republicans are in the middle, with 21 percent 65 and older and 16 percent under 30. Unaffiliated voters are the youngest, with 19 percent 65 and older and 23 percent under 30.

— The 1st Congressional District, currently represented by David N. Cicilline, is the most heavily Democratic, with 44 percent registered with that party, 9 percent Republicans and 47 percent unaffiliated. The 2nd Congressional District, currently represented by Jim Langevin, is 35 percent Democrats, 12 percent Republicans and 54 percent unaffiliated. These numbers are important because some of the delegates of each party will be allocated in proportion to the vote in each congressional district.

On the lighter side: Cruz is the most popular last name among voters who share a name with a candidate, more popular than Kasich, Trump, Clinton and Sanders combined, though Cruz is more popular with Democrats than Republicans.

Among Republican candidates, John Kasich has the most popular first name, with 13,576 voters sharing the name, followed by Donald Trump, with 2,843 ("Donalds" plus "Dons"). Ted Cruz only has 56 voters sharing his name, but that climbs to 552 if you include Rafael, Cruz's first name. Ted is a nickname for Edward, his middle name.

Among Democrats, Bernie has 11, which climbs to 381 if you count Bernard, and Hillary has 231, if you aren't fussy about how many L's you use.

R.I. PRIMARY VOTER'S GUIDE

Who may vote

Anyone registered with a party may vote in that party’s primary. Unaffiliated voters may vote in either primary, but only one.

Hours

Polling opening times vary from 7 a.m. to 9 a.m. in most of Rhode Island, noon on Block Island. All polls close at 8 p.m.

Polling locations

For presidential primaries, the state typically opens only about one-third of polls. That means that many voters will be sent to a different location Tuesday. Signs will be posted at closed polling locations advising voters where to vote.

Find out where to vote

Look up your polling place, hours and more at the state’s online voter information center: http://sos.ri.gov/vic

Voter ID

Remember to bring a government-issued photo ID to speed your check-in at the polling place.