i don't see it happening. i think well actually see an INCREASE in march (and maybe even february because of VF5). from then on, i think well see numbers higher than january as more games are released. Feb has VF5, Tekken 5 DR and F1 CE. March as Motorstorm, MLB 2K7, NBA Street HC, FEAR, Def Jam Icon, Oblivion and SC DA. April has R6 Vegas, MLB The Show. May has Saints Row and Lair. and June is another big month with Heavenly Sword, Ninja Gaiden Sigma, GRAW2, Warhawk, Rogue Warrior and Singstar.
so yeah, i think starting march (or even february) sales will start to increase in N/A. and starting March 23rd, worldwide sales will increase significantly due to the European launch.