Via Slate’s Rachael Larimore: China and India has aborted more girls (160 million) than America has women.
Larimore’s article does the same dance that Mara Hvistendahl does in her Unnatural Selection: Choosing Boys Over Girls, and the Consequences of a World Full of Men: note that gender imbalances are caused by abortion without blaming abortion. Of course, there are other issues at play including coercive population control measures (that rely on abortion as birth control as last resort) and cultural preferences for boys (which leads to the culling of the girl population by abortion), but the problem of gendercide is driven by abortion, abortion, and more abortion.