In 1981 the national debt was $0.998 trillion
In 1989 the national debt was $2.857 trillion
It tripled under Reagan.
In
constant dollars, the national debt in 1989 ($2.857 trillion) compared to that in 1981 ($0.998 trillion) was about ~1.99 to 0.998 or about 2:1.
In constant dollars, the national debt in 2012 (~$16 trillion) compared to that in 2009 (~$10 trillion) was about ~$15 trillion to ~$10 trillion or about 1.5:1.
Over 8 years of Reagan (actually 8 years of Democrat control of both houses of Congress), the debt, in constant dollars, increased about 100% or 12.5% for each of the eight years.
Over less than 4 years of Obama (2 years of Democrat control with super-majorities of both houses of Congress, a Democrat president, and 4 years of Harry Reid obstructionism in the Senate), the debt, in constant dollars, increased about 50% over 3.5 years or about 14.3% per year (about a 14% yearly increase over the 12.5% per year of the Reagan years).
So, the national debt has increased by at least the same rate during Obama as during Reagan for exactly the same reasons: baseline budgeting and Democrat control.