The other four did not affiliate with any political party when they registered to vote and none of them voted in this year's Democratic primary. All 15 voted this November.
"Mormons have always been politically diverse" historically, says Max Perry Mueller, an associate editor at the John C. Danforth Center on Religion & Politics at Washington University in St. Louis. "I think now is a time of less political diversity and that might be because of the lack of political diversity at the top."
And he thinks that some LDS adherents may take political cues from their religious leaders.
"As the prophet goes, so goes his flock," Mueller said, "maybe even more today than in [church founder] Joseph Smith's time."
The four politically unaffiliated apostles are the governing First Presidency's second counselor, Dieter F. Uchtdorf; and David A. Bednar, Quentin L. Cook and D. Todd Christofferson, of the Quorum of Twelve Apostles.
Uchtdorf who was born in the Czech Republic and only recently became a U.S. citizen did, however, register as a Republican to vote in the primary this year and then changed his registration back to unaffiliated.
The strong Republican tilt at the top is in line with political leanings of the vast majority of Mormons throughout the United States. The Tribune review shows that at least 73 percent of the 15 leaders at the top of the LDS hierarchy is demonstrably Republican, while a Pew poll released in January found that 74 percent of all American Mormons who are registered to vote say they are Republican or lean Republican.
Romney captured 78 percent of the Mormon vote nationwide this November and 90 percent of the Mormon vote in Utah in his unsuccessful bid to unseat President Barack Obama.
And, in Congress, where 16 members are Mormon, 12 are Republican, or 75 percent. The Democrats include Senate Majority Leader Harry Reid, of Nevada, and Rep. Jim Matheson, of Utah.
LDS Church spokesman Scott Trotter says party affiliation and voting are personal matters for individuals, even church leaders, and he warned people not to read too much into the voting-registration records.
Preaching gospel, not politics • "Party affiliation does not necessarily indicate how an individual votes," Trotter said. "As an institution, the church is politically neutral. The purpose of the church is to preach the gospel of Jesus Christ."
Furthermore, Trotter said, the church stresses that "good can be found in the platforms of various political parties" and that the church does not dictate to Mormons how they should be involved in the political process.
For Sen. Orrin Hatch, a Utah Republican and Mormon, the fact that so many top leaders of his faith are registered Republicans doesn't change anything.
"They're just as good to Democrats as they've been to Republicans and I don't think they're political," Hatch said, noting he wasn't aware of the apostles' party registration. "My experience is they're not political. They just want to do what's right."
But the political leanings of those steering the church is a concern among Democrats, particularly in Utah, where they took great pains this past election to show their party, too, caters to Mormons and includes many within its fold.
The state party launched a new caucus, the LDS Democrats, hoping that gaining even a bit of headway could impact elections in Utah and surrounding states with high Mormon populations.
"Perhaps some of the reason we have become incredibly Republican is because we have had more Republican leaders in the last two or three decades," said Crystal Young-Otterstrom, chairwoman of the LDS Democrats, who was unaware but not surprised by the high number of top LDS leaders registered as Republican.
"It certainly shows the work we need to do," she said. "It would be great to have someone openly say they are a Democrat."
She keeps tabs on high-profile Mormon Democrats to counter people who argue that good Mormons can't also be Democrats, and she points to a recent addition to the Quorum of the Seventy, a leadership body directly below the apostles.
Larry Echo Hawk left the Obama administration, where he served as the director of the Bureau of Indian Affairs, to take the LDS Church position. He previously served as Democratic attorney general of Idaho and was the party's nominee for Idaho governor in 1994.
LDS leaders haven't always been so pro-Republican during the faith's 182-year history.
GOP vs. LDS • Church founder Joseph Smith ran for president as a minor-party candidate in 1844, espousing his thoughts on slavery, foreign policy and a centralized government. He rallied against the Whigs and Democrats.
Later on, the Republican Party launched itself on the national scene in the 1850s by calling out the "two relics of barbarism" slavery and polygamy, the latter a direct reference to the then-Mormon practice of men taking on multiple wives. Mormon leader Brigham Young castigated the Republican Party at the time, calling it out as anti-Mormon.
In the worst moments, Republicans in Congress pushed legislation to dissolve the LDS Church and for four years after his election refused to seat the first Mormon elected to the U.S. Senate: apostle Reed Smoot.
Mormons eventually moved toward the Republican tent in the second half of the20th century in part because of a focus on social issues, including gay marriage and abortion, which the LDS Churchconsiders moral causes.
There have been some high-profile partisans in LDS leadership, such as then-apostle James E. Faust, who served one term in Utah's Legislature as a Democrat, 1949-50, and later as the chairman of the state Democratic Party. Faust rose to the ranks of second counselor in the First Presidency, where he served until he died in 2007.
And then there was Ezra Taft Benson, who was named an apostle before serving as President Dwight Eisenhower's agriculture secretary. The LDS Church has since banned apostles from holding political posts.
Republican tilt • Mueller, who is not Mormon, has studied the LDS Church's political history in Utah from its roots as a theocracy under Young to the church's more recent partisan neutrality.
He said the GOP leanings of top officials shouldn't surprise anyone who has followed the faith's stance on social issues.
"The church is making a concerted effort to present itself, in terms of party politics, as neutral, but there happens to be a party that much more aligns itself with what they would say are questions of morality," Mueller said, though he also sought to qualify what the voting registration records show. "They are Republicans as individuals, not as prophets."
The LDS Church is officially politically neutral in part because the U.S. tax code forbids nonprofits from getting involved in campaigns for political office, but the church may also not want to offend its worldwide membership, which includes a wide variety of political leanings.
"I see the church becoming more and more apolitical because it does want to make itself a bigger tent," said Mueller, noting the LDS Church didn't get involved in gay marriage ballot initiatives in states such as Maryland as it has in the past in California and Hawaii.
The fact so many top LDS leaders are aligned with the GOP may be a reflection of Utah politics, where many top races are decided in Republican conventions or closed primaries.
Overall, 44 percent of Utah's registered voters on Election Day were Republican, 46 percent were unaffiliated and just a little over 9 percent were registered Democrats, according to state election officials.
While the state is predominately conservative, these party numbers exaggerate the state's actual party split because the GOP allows only registered Republicans to vote in primary contests, while the Democrats do not have that requirement.
Sen. Mike Lee, who is also Mormon and a Republican, says he's a little surprised by the GOP leanings of the LDS Church's top leaders, but welcomes it.
"I didn't realize there were no registered Democrats among them," Lee said, quickly adding, "I'm glad to know most of them are Republicans. That's great."
Dan Harrie contributed to this report.