The way you can help yourself cut back on those is by not answering in any way if you're able. Most quick hang ups are simply fishing for numbers that have any kind of answer, especially after business hours. It may even be a computer doing the calling to hit a slew of numbers at the same time. Ones with answers can be resold to other pests to bother you, too. No kind of answer gives you a chance to not have your number passed along.