Thanks to improved healthcare, sanitation and vaccination in the last 100 years or so, the risk of dying from influenza has decreased substantially — but the flu still kills hundreds of thousands of people around the world annually.

The flu is believed to be deadlier in South American, African and South Asian countries — more than in Europe or North America — due in part to higher levels of poverty, worse underlying health and poorer access to healthcare.

Our World In Data used estimates from the Global Pandemic Mortality Project II to illustrate the average flu mortality in over-65s between 2002 and 2011.

It's difficult to get an exact number on flu deaths worldwide for a few reasons — for example, the symptoms of influenza resemble those of several other infections, and it can cause deaths in indirect ways such as pneumonia or heart attacks.

The authors also note that estimates tend to be less certain in low-income countries, where there is less testing for influenza and limited mortality records.

According to these figures, though, seasonal influenza killed between 294,000 and 518,000 people each year globally. Europe's flu death rate in over-65s was 30.8 people per 100,000 — the lowest rate worldwide — while South-East Asia, with an average mortality of 71.2, saw the highest number of deaths.

Via Our World In Data.