Why did the author mention the proportion of Americans who are expect to turn out to vote?

On Tuesday, some 37 percent of Americans are expected to turn out to vote-On Sunday, some 66 percent of Americans celebrated Halloween.
    Halloween is a holiday with ancient pagan roots, hut the modern extravaganza of candy, pumpkins and sexy nurse costumes is as American as the Fourth of July. Some experts on folk customs trace Halloween to an ancient Celtic holiday in the British Isles. But until recently, the British had long forgotten the day: (24) Two decades ago, Halloween hardly existed in the United Kingdom, never mind continental Europe or Japan.
    All that has changed in the blink of an eye. Halloween has gone global—and Halloween’s success tells us something interesting about the modern world. The British grocery chain Tesco sold 1.4 million pumpkins on Sunday. The chain estimates that its Halloween sales have tripled since 2005. British parks sponsored free Halloween spectacles: ghost walks and pumpkin carving. Trick-or-treating is spreading through London neighborhoods.