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Greece and Puerto Rico are both spiraling toward default, with billions of dollars worth of debt that their governments aren't able to pay off for years and neither is able to devalue its currency. Both are also struggling with widespread tax evasion, government corruption and a lack of transparency in public governance.

But the similarities pretty much end there.

"Detroit is probably a better comparison than Greece for the situation in Puerto Rico," Matt Fabian, a partner at the Connecticut-based Municipal Market Advisors financial planners, told Fox News Latino. "Both have rapidly shrinking economies and rapidly declining populations."

The Motor City filed for bankruptcy in 2013 in an attempt to escape its debt load. Puerto Rico, however, cannot legally file for bankruptcy.

Puerto Rico’s governor announced this week that the commonwealth could not pay off $72 billion in bond debts and $50 billion in pension and healthcare it promised to retirees. Greece, which is $263 billion in debt, on Tuesday defaulted on a loan to the International Monetary Fund.

The political process in the U.S., while very complex, pales in comparison to the process in Europe, meaning that the cost of restructuring Puerto Rico's debt is expected to be far lower than that of bailing out Greece. And while the White House has said that it would not bail out Puerto Rico, the U.S. could help the commonwealth recover in other ways, helping cushion the fall.

What people refer to as the "Grexit" – meaning Greece leaving the Eurozone – would have a greater impact on Europe.

"As far as contagion effects go, Puerto Rico is missing virtually all of the broader geopolitical and humanitarian implications of a 'Grexit,'" Bank of America economist Ethan S. Harris wrote in a research note to clients. "It is, therefore, difficult to see a Puerto Rico default as a significant source of contagion that would materially impact the Fed's policy decisions. The risk of global contagion from Grexit, while apparently low, arguably looms larger on the Fed's radar — it has been cited as a risk to the outlook several times in this year's [Federal Open Market Committee] minutes; Puerto Rico has not once been cited."

Neither Puerto Rico nor Greece have the option of devaluing the U.S. dollar or the Euro, which would give their companies a price advantage in world markets and could jump-start economic growth with exports.

"There are too many creditors," Steven Rhodes, a former U.S. bankruptcy judge who oversaw Detroit's case who now advises the Puerto Rican government, told the Detroit Free Press. "Like Detroit, Puerto Rico can't print money. So Puerto Rico's insolvency is as much the creditors' problem as it is the commonwealth's problem."

Puerto Rico and Greece’s financial situation will not have the same ripple effect that the 2007 U.S. mortgage crisis and Europe’s 2009 sovereign debt had on global markets.

But any impact they have on the world’s finances will be felt in the coming weeks, or months.

Compounding the issue in Puerto Rico – as it did in Detroit – is that people are fleeing. Puerto Rico's population loss is approaching 1 percent, which is 10 times worse than that of any U.S. state.

Thousands are also fleeing Greece, which has seen a 3 percent population drop since the crisis began. About 300,000 people have left Greece since 2010, according to The New York Times.

Detroit's population fell drastically in the second half of the 20th century, from nearly 2 million in the 1950s to fewer than 700,000 today.

"Puerto Rico is where Detroit was in the 1970s," Fabian said. "People are pulling off the island for Florida and other parts of the United States."

That sort of population loss not only undercuts Puerto Rico's tax base, which makes it difficult to pay back its debts, it also drains the island of young talent that could help the territory rebuild.

The people left in both Puerto Rico and Greece are getting older on average and a high percentage are government employees, which means that many will be retiring and trying to draw on their pensions.

Another big difference between Puerto Rico and Greece is the population's reaction. While tens of thousands of Greeks have hit the streets in anger over austerity measures, the reaction is Puerto Rico has been more subdued. On Wednesday, anger over an increase in sales tax in Puerto Rico drew few dozen people.

One of the biggest worries for Puerto Rico is that there's no chance of a government bailout. The island cannot seek emergency financing from an institution because it's a U.S. territory. Some economists say that leaves bankruptcy as the most financially sound alternative, something U.S. rules do not currently allow.

"Both [Greece and Puerto Rico] are in desperate need of a solution, but neither can access the solution they're asking for, which is a bankruptcy process," said Eric LeCompte, executive director of Jubilee USA Network.

He noted that if Puerto Rico were considered a developing country, it would be the eighth most-leveraged economy in the world. If the island does not gain the right to declare bankruptcy, it will have to restructure its debt or go into default, he said.

"That's going to happen," he said. "[Puerto Rico] is between a rock and a hard place in terms of how to move forward."

Critics of allowing the Puerto Rican government to declare bankruptcy argue that it would be unfair to people who own bonds issued by the island.

The "proposed solution comes at the expense of seniors and retirees who invested in the island in good faith. Moreover, it does nothing to improve the reckless and even corrupt policies and practices that have left the island all but bankrupt," the 60 Plus Association, a Virginia-based senior rights group, said in a statement.

The White House has said that no one is contemplating a federal bailout of Puerto Rico, although it has urged Congress to consider changing the law to allow the island's government and public agencies to seek bankruptcy protection under Chapter 9.

Puerto Rico could obtain that right if officials realize there is no other solution, said John Mousseau, fixed income director at Florida-based Cumberland Advisors.

"Some people say there's nothing the federal government can do for Puerto Rico," Mousseau said. "That's baloney. It's clearly at some level a Congressional problem that they're doing nothing about."

The Associated Press contributed to this report.