The number of American troops killed in Afghanistan dropped dramatically in November, to one U.S. death.

The only U.S. military death recorded last month came when a suicide bomber rammed his car into a military convoy on Nov. 13.

U.S. military spokesman Col. Jerry O'Hare says insurgents in Afghanistan typically scale back operations during the winter months, and that could account for some of the drop in deaths in November.

But he also attributed the drop to better tactics and an improvement in Afghanistan's own security forces.

Military statistics show U.S. troops suffered an average of 21 deaths each month from May through October this year. Sixteen soldiers died in October. Twenty-five died in September.