When Britain voted in June to leave the EU, a key reason was resentment at the 3 million other EU citizens living in the UK. But of course, there are British citizens—1.3 million of them—living elsewhere in the EU. And as a brief discussion last week in parliament shows, in this exchange of citizenry, Britain probably has by far the better end of the bargain.

On Nov. 24, parliament’s public accounts select committee was examining the question of how health benefits would work for British senior citizens abroad and EU senior citizens in Britain after Brexit. John Crace, the Guardian’s parliamentary sketch writer, described the exchange:

During a question about reciprocal healthcare arrangements for foreign pensioners, the chair, Meg Hillier, asked Wormald if he had any comparative figures for Spain. “Yes,” he said promptly. “At our last count there are 62 Spanish … ” “Not 62,000?” interrupted the Conservative Richard Bacon. “62 Spanish pensioners,” said Hillier. “You’re kidding me.” “62 Spanish pensioners live in the UK and about 70,000 British pensioners live in Spain,” replied the bewildered Wormald, who couldn’t see what the fuss was about. “62?” Hillier repeated incredulously. “We are not the retirement place of choice,” Wormald explained.

That remarkable statistic symbolizes the imbalance between the kinds of people Britain exports and imports. Foreign-born workers in Britain are slightly younger on average than their UK-born counterparts, according to a recent report (pdf) by the University of Oxford. And over the last 20 years the proportion of foreign-born workers aged 25-35 has increased sharply, while mostly falling for older age groups. For UK-born workers, it’s the opposite trend: The workforce has aged overall.

Those data don’t distinguish EU from non-EU immigrants. However, there are some clues in a 2014 report by University College London, which found that the average age of migrants to the UK from western Europe—such as France, Italy and Spain—was 27. For migrants from the 10 central and eastern European countries that joined in the EU in 2004 or 2007, it was 26. European migrants who had arrived since 2000 were also, on average, better educated than their British counterparts.

There aren’t clear figures for the average age of British migrants in the EU, but in Spain, which hosts the largest group of British migrants—estimated 310,000—they are thought to be much older (paywall) and less healthy, on average, than their native counterparts. And if 70,000 are past retirement age, that’s especially likely to be true.

It may be true that European immigrants have been taking British jobs—but they’ve also been contributing more to the economy than they take out of it. When Britain leaves the EU, it’ll be paying the price.