The internet is a place known to be X-rated at times, but just how much of the it is porn and other adult content? Numbers as high as 30 percent get thrown around when discussing that question. The truth might be a little less sleazy, but scientific data is hard to come by in this case. The newest numbers available are from between 2005 and 2014. Two studies, one by computational neuroscientists Ogas and Gaddam from Boston University and another joint one by Google and Columbia University , suggest that the share might be much lower. Only 4 percent of websites are estimated to be porn, but web and mobile searches clock in higher at 13 and 20 percent respectively . But as always, the internet changes quickly, and new studies might bring about new insights.In recent years, several U.S. states have seen legislation introduced to combat a perceived prevalence of online porn. Most recently in Hawaii and Arizona state lawmakers have brought forward bills that would charge users a one-time US$20 fee before unblocking all internet porn. The proceeds would go towards helping the victims of sex trafficking or, in the case of Arizona, help build Trump’s border wall. Religious lobbying group Special Forces of Liberty is behind his coordinated effort.So why are some estimates of the amount of online porn so high? The internet might have been a dirtier place in the 1990. In those days, it had limited services and a limited user base. A 40 percent share of pornographic online searches was likely a reality then, according to Ogas and Gaddam.