You’re reading Significant Digits, a daily digest of the numbers tucked inside the news.

330 feet long and 200 feet across

Despite the internet and Wikipedia and satellites and ubiquitous smartphones and video cameras, we don’t know everything. And the list of things we didn’t know included, until recently, the existence of a very large cave — big enough that it could hold the Statue of Liberty — in Wells Gray Provincial Park in British Columbia, Canada. As you no doubt already guessed, given the setting, the cave was discovered by biologists performing a caribou census. [The New York Times]

19 beatifications

Nineteen Catholics killed in Algeria’s civil war in the 1990s and early 2000s — including Trappist monks and a bishop — were beatified, an official step on the path to sainthood. They were the first beatifications performed in a Muslim nation. [BBC]

97 percent decline in butterflies

Speaking of animal censuses, some 4.5 million monarch butterflies (or more) spent their winters in California in the 1980s. These days, that number is down to 30,000. Overall monarch counts in the West are down some 97 percent. A biology student at the University of California, Santa Cruz, called it “a sad reality of climate change.” Drought and severe weather are “deadly stressors” for monarchs. [The Guardian]

10 to 15 mph

Thanks to NASA’s InSight lander, we have the first ever recordings of the “sound” of Martian wind. This wasn’t the plan — InSight’s seismometer sensors were designed to measure geological planetary motion, but sound waves cause motion, too. The lander captured “a haunting low rumble” of the 10 to 15 mph blowing on the red planet. [NASA JPL]

99.8 percent chance

The draw for the 2019 Women’s World Cup was held over the weekend, and the U.S. drew an easy group — it’ll be joined by Sweden, Thailand and Chile. So easy, in fact, that the team has a 99.8 percent chance of advancing to the Round of 16, according to the Soccer Power Index. France, the tournament’s host, drew the toughest group — with South Korea, Norway and Nigeria — but even still has a 94.9 percent chance to advance. The tournament begins in June. [FiveThirtyEight]

Between 20 and 22 percent

Between 20 and 22 percent of NPR’s 483 union-covered staff are temps, according to union reps. This is unusual. By comparison, according to a recent industry survey, about 5 percent of a typical TV station’s staff is temporary or part-time, and radio stations average just one part-timer or temp. Several temps described NPR’s system to the Washington Post as “exploitative.” NPR’s president of operations said the system was in place because NPR is a “media company that strives to be innovative and nimble.” [The Washington Post]

Love digits? Find even more in FiveThirtyEight’s new book of math and logic puzzles, “The Riddler.” It’s in stores now! I hope you dig it.

If you see a significant digit in the wild, please send it to @ollie.