Peru officials revised the country's COVID-19 death toll Monday from 69,342 to 180,764 after a review.

Why it matters: The almost tripling of the number listed Sunday means the country has the worst pandemic death rate per capita, according to Johns Hopkins University data.

By the numbers: Per Johns Hopkins, Hungary previously had the highest coronavirus death toll per capita —about 300 per 100,000 people.

• With its revised toll, Peru stands at over 500 COVID-19 deaths per 100,000 people.

Driving the news: Officials said that the undercounting was partially down to "a lack of testing that made it difficult to confirm whether a person had died due to the virus or some other cause," Reuters reports.

• Experts had long raised concerns that the official death toll had been undercounted, as hospitals packed out with coronavirus patients and oxygen ran short, the news agency notes.

What to watch: The revised numbers come ahead of a hotly contested June 6 presidential election runoff between the leftist Pedro Castillo and former lawmaker Keiko Fujimori.