well that trend is clearly down but there could be other factors. the one that comes to mind is most of these films were post-processed for 3D rather than filmed for 3D which makes that extra few bucks kind of a waste. also, why didn't they include all films released in 3D? Alice in wonderland and clash of the titans come to mind, i think they are missing another movie or two as well.
but as a lover of 3D i find that trend to be disturbing.