https://arstechnica.com/information-technology/2017/09/equifax-website-hack-exposes-data-for-143-million-us-consumers/

Equifax, a provider of consumer credit reports, said it experienced a data breach affecting as many as 143 million US people after criminals exploited a vulnerability on its website. The US population is about 324 million people, so that's about 44 percent of its population.

The data exposed in the hack includes names, Social Security numbers, birth dates, addresses, and, in some cases, driver license numbers. The hackers also accessed credit card numbers for 209,000 US consumers and dispute documents with personal identifying information for about 182,000 US people. Limited personal information for an unknown number of Canadian and UK residents was also exposed. Equifax—which also provides credit monitoring services for people whose personal information is exposed—said the unauthorized access occurred from mid-May through July.