This is admittedly a tough table to understand at first glance, but the conclusion is pretty scary.
First, they take USA's total debt, and figure out how much debt that is per person.
Then they take USA's Gross Domestic Product, and figure out how much GDP that is per person.
Then they figure the ratio.
In 1995, our ratio was 0.082. Now it's 0.712. The only Latin American country that is higher is Argentina, and we're clearly in the same ballpark. More ammo for Krugman's view that our deficit could be leading us into a latin-america-style fiscal crisis... go take a look.
In short, deficit very very very bad.