This is because large prizes are expensive to pay out, so the smaller sized wins come much less regularly to compensate. https://www.asturmedia.com/%EC%95%88%EC%A0%84%ED%95%9C-%EB%9D%BC%EC%9D%B4%EB%B8%8C%EB%B0%94%EC%B9%B4%EB%9D%BC-%EB%B2%A0%ED%8C%85-%EC%84%B1%EA%B3%B5%EC%A0%81%EC%9D%B8-%EA%B2%8C%EC%9E%84%EC%9D%84-%EC%9C%84%ED%95%9C-%ED%95%84/