Big data can come from small places.

Iceland’s isolated location and sparse population mean that some vital information about the novel coronavirus is coming out of the island nation — especially considering that it’s already tested 10% of its population, which is more than any other country, according to USA Today.

And the scariest finding: At any given time, about half of its citizens who have the coronavirus — and don’t know it — are not showing any symptoms. That’s double the CDC’s recent estimate that as many as one in four people with COVID-19 may be asymptomatic.

Granted, the United States hasn’t tested such a high percentage of its population, so it’s not working with as much data. Online statistics site Worldometer crunched the number of coronavirus tests reported by each state — around 2.3 million, by its account, in total — which it equated to about 7,100 tests per 1 million people. By that same scale, it reported Iceland has performed 96,000 tests per million people. (The actual population of Iceland, long a favorite of biotech research because of its relative homogeneity and its centuries’ worth of genealogical records, is 364,134 — roughly the same as that of Tulsa, Okla.)

President Trump said in an April 6 press briefing that almost 2 million Americans, or 0.6% of the U.S. population, had been tested for COVID-19. The recent report from the Department of Health and Human Services inspector-general also warned of testing-supply shortages and long wait times.

So that means the “best data” on coronavirus is coming from Iceland at the moment, John P.A. Ioannidis of Stanford University told USA Today. And Kari Stefansson, CEO of deCODE genetics, which is helping to carry out Iceland’s testing efforts, said that Iceland may be one of the best live coronavirus laboratories we have in the world as it continues to randomly test its people.

And it’s already made some important discoveries. Among them: that between 0.3% and 0.8% of Iceland’s population is infected with the coronavirus, while half of those who tested positive were asymptomatic as the time of their tests.

“That’s a bit scary,” said Stefansson. “They could be spreading it and not knowing it.”

But since mid-March, the prevalence of COVID-19 among Iceland’s general population that’s not at the greatest risk — that is, not of advanced age or with underlying health conditions — has either stayed stable or decreased, showing that social-distancing and containment efforts are working.

While Iceland has not imposed a national lockdown, and many shops and businesses are still open, it has banned gatherings of more than 20 people. It’s otherwise mostly relying on a trust system that its citizens are practicing isolation and social distancing. As of April 10, the country counted more than 1,600 coronavirus infections and six deaths.

For the most current information on coronavirus in the U.S., including tips on social distancing, check out MarketWatch’s coverage here.