Query: As of June 2015, how many estimated visitors does youtube have in a month?
Context: It is estimated that in 2007 YouTube consumed as much bandwidth as the entire Internet in 2000. According to third-party web analytics providers, Alexa and SimilarWeb, YouTube is the third most visited website in the world, as of June 2015; SimilarWeb also lists YouTube as the top TV and video website globally, attracting more than 15 billion visitors per month.