Long-term interest rate projections

Here are the only numbers I can find for long-term interest rates, from the OMB.

10-year Treasury notes:
2011 3.0%
2012 3.6%
2013 4.2%
2014 4.6%
2015 5.0%
2016 5.2%
2017 5.3%
2018 5.3%
2019 5.3%
2020 5.3%
2021 5.3%

If the debt is 30 trillion in 2021, then 5.3% interest would be 1.59 trillion per year.