You also need to account for student debt. In most EU countries, students do not need to go in debt to pay for university. So in the US, how much of those first

You also need to account for student debt. In most EU countries, students do not need to go in debt to pay for university. So in the US, how much of those first salaries goes to paying back that debt? (It won't account for the complete difference obviously.) And maybe retirement savings is another thing to add.