This chart is from Jeffrey Gundlach’s April 26,2012 presentation (the chart is reproduced here), and it’s terrifying. Note that every 1% rise in rates means an additional $150 billion or so in debt service cost.
Above the Market
Perspectives on capital markets and personal finance
Above the Market 
You might need to provide more background on this, as the chart does not mean much to the average person.
This chart shows 2012 U.S. bond redemptions that will need to be refinanced by the government this year via new issuance. It’s an interesting look into how much money we owe.