The number of deaths also declined because U.S. soldiers found and defused more roadside bombs, Khaama Press reported Saturday.
Improvised explosive devices, or IEDs, killed 104 U.S. troops in Afghanistan in 2012 compared to 196 in 2011, a 46 percent drop.
The number of troops wounded by the devices fell 50 percent, from 3,542 in 2011 to 1,744 last year.
IED attacks dropped by about 8 percent in 2012 from a record high the year before, Pentagon data showed, as Afghan soldiers shouldered more responsibility for combat.
Consequently, IED attacks against Afghan troops increased 124 percent in 2012, the records showed.