Mexico’s health ministry announced on Friday that about a quarter of the country’s 126 million people are estimated to have contracted COVID-19, far more than Mexico’s confirmed infections.

The 2020 National Health and Nutrition Survey (Ensanut) revealed that nearly 31.1 million people have been infected with the virus, the ministry said in a statement, quoting Tonatiuh Barrientos, an official at the National Institute of Public Health.

The estimate was given as Mexico reported 3,282 new infections and 243 more deaths, bringing its total number of confirmed cases to 2,448,820 and the death toll to 229,823.

The cabinet has announced previously that the real number of infections was likely to be significantly higher.

Not all of the people in the survey’s estimate necessarily had symptoms, according to Barrientos. The survey was based on interviews with people at 13,910 households between Aug. 17 and Nov. 14 last year, and confirmed preliminary results released in December.

Separate data published in March suggested the country’s actual death toll was at least 60% above the confirmed figure.