One-fifth of all living Mexican-born people live in US

This statement from David Frum is an amazing statement. It is incredible how a government can so mess up its economy.

Today, almost one-fifth of all living Mexican-born people now make their homes in the United States. You have to go back to the Irish potato famine to find a parallel. But Mexico is not suffering famine: It is suffering from a comprehensive failure of political and economic leadership.

If this is correct, it implies that something around 25 million mexican-born people live in the US.