U.S. federal government interest payments

The Committee for a Responsible Federal Budget asks: How High Are Federal Interest Payments?

It will be about $300 billion this year. The amount of U.S. federal debt is $28 trillion. So the average interest rate paid on that debt is $300 billion/$28 trillion = 1.07%. In the early 1980s the aggregate or average interest rate on Treasury securities was over 8%. Interest rates on new 30-year bonds exceeded 14%, and rates on short-term issues exceeded 17%. Reaching an aggregate 8% again seems very improbable, but reaching 3% or 4% is not. Of course, reaching 3% or 4% instead of the current 1% implies the federal government's interest payments would triple or quadruple, and this would put pressure on other federal government spending. That's except to those unconcerned about deficits and debt, which includes the majority of politicians and bureaucrats.

Page 24 here shows (as of 6 months ago) when Treasury securities mature (and will be replaced by new issues).  Most mature within 5 years, so the aggregate interest rate will lag a rise of interest rates on new issues, but not for a long time (unlike all securities being long-dated).  

The graph on this page shows how the yield on 10-year Treasury bonds have risen this year from about 0.9% to 1.6%