Hard on the heels of back to school sales, Halloween costumes are selling like hotcakes right now. Topping the children's costume list are superheros, princesses and some old favorites. Although stranger danger, candy safety, religious objections and the fear factor worry some parents, the trend to celebrate Halloween is growing. It's also a very lucrative holiday for merchandisers. Here's a look at Halloween facts and figures by the numbers. Halloween Costumes, Candy, Kids Festivities--By the Numbers.