Like déjà vu, Floridians are in the middle of a contentious and closely-watched recount for multiple races.

Once the machine recount is complete, state law requires a hand review of races with margins of less than 0.25 percentage points. This almost certainly means another recount in the Senate race, with unofficial results showing Republican Gov. Rick Scott ahead of incumbent Democratic Sen. Bill Nelson by 0.14 percentage points.

But the machine recount may bring a conclusion to the governor's race, where Republican Ron DeSantis leads Democrat Andrew Gillum by 0.41 percentage points in unofficial results.

According to FiveThirtyEight, recount efforts rarely change the original outcome.

“I think there’s real value in post-election audits, in large part to catch something systemic — even more so for a big election like president, and with our Electoral College rules that can exaggerate the impact of results in one or two states,” Rob Richie, executive director of FairVote, told the news outlet. “But as a general matter, the likelihood of a statewide recount having an impact on outcome is extremely small unless the original outcome is exceptionally close.”

Read on for a look at a few infamous recount efforts in U.S. political history.

2016 presidential election (Wisconsin)

Green Party presidential nominee Jill Stein paid for a recount in Wisconsin, a swing-state – an effort she said was to “ensure the integrity of our elections.”

It didn’t take long for the recount to be completed, and it just added more votes to Donald Trump’s total. The eventual president had already won Wisconsin, beating Democrat Hillary Clinton.

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Stein raised several million dollars for her recount efforts. She was encouraged to pursue a recount after Clinton declined to do so, The Daily Beast reported.

2008 Minnesota Senate

At the time, the U.S. Senate race in Minnesota between incumbent Republican Norm Coleman and Democrat Al Franken was dubbed “the longest, closest and costliest” in the state’s history.

As Coleman’s lead over Franken dwindled to about seven-thousandths of one percent, state law mandated a strict hand recount.

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Franken ended up emerging victorious six months after the election with a lead of 312 votes, according to the St. Paul Pioneer Press.

2004 Washington governor

The 2004 Washington gubernatorial race was so contentious, it required a recount – twice.

When it was all said and done, Democrat Christine Gregoire beat Republican Dino Rossi by just 130 votes, according to the Seattle Times. Rossi had initially been declared the winner.

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It took 58 days for Gregoire to be declared the governor-elect, The New York Times reported.

2000 presidential election (Florida)

Perhaps the most famous recount in U.S. political history was the 2000 presidential election between George W. Bush and Al Gore. Florida was widely scorned for how it handled the recount effort as it didn’t have uniform rules on how to do so.

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Bush ultimately won Florida with 537 votes out of nearly 6 million cast.

Gore locked in the popular vote, but Bush won the Electoral College after the Supreme Court halted the recounts in Florida. As vice president, Gore also presided over Congress when it officially certified Bush the presidential winner.

The Associated Press contributed to this report.