Children who have a large number of books in the house when they’re growing up tend to be higher earners later in life, according to a new study published in the Economic Journal.

Economists Giorgio Brunello, Guglielmo Weber and Christoph Weiss of the University of Padua looked 6,000 men born in nine European countries in the mid-20th century. Subjects were categorised depending on whether they had fewer than 10 books at home, a shelf of books, a bookcase with up to 100 books, two bookcases, or more than two bookcases.

Researchers estimated the effect of education on lifetime earnings by “distinguishing between individuals who lived in rural or urban areas during childhood and between individuals with access to many or few books at home at age 10.”

“Whereas individuals in rural areas were most affected by [school] reforms [over the period studied], those with many books enjoyed substantially higher returns to their additional education.”

An extra year of schooling was found increased a man’s average lifetime earnings by 9%. However, those brought up with very few books at home only saw a 5% rise in lifetime earnings resulting from an extra year’s education. For those with a large number of books, the rise was 21%.