Putting in Jan 21, 2009 and Nov 12, 2009 as the date range we get:
10.625 trillion and 11.987 trillion, respectively – a 12.8% increase in the national debt.
…
Putting in the Bush era – Jan 21, 2001 to Jan 20, 2009, however, we get:
5.728 trillion and 10.627 trillion, respectively — an 85.5% increase (that is, a near doubling) of the national debt.
Make sure you are using equal timespans. You are comparing less than a year (9months) to an 8 year time span.. If we continue at the current rate over the length of time Bush was president, national debt will increase by ((8 * 12)/ 9) * (12.8/100) = 136.5%… unless the relation is geometric which means (e^((ln 1.128)/9))^(8*12) = 261.4% or a multiple of 3.614x of what Bush left it at.
