To even imply that 15 semifinalists is somehow subpar is ludicrous. The students who earned that distinction should be very proud of themselves, but neither they nor this school should let numbers get to their heads. This school's academic climate focuses so narrowly on perfection and national recognition as to obscure legitimate achievements that are not captured by a three hour test. In short: to answer your question "Why the decline?" I would respond "Why does it matter?"