Article: Within the past ten years, the amount of social networking sites available to the public has greatly increased as well as the number of adolescents using them. Several sources report a high proportion of adolescents who use social media: 73% of 12–17 year olds reported having at least one social networking profile; two-thirds (68%) of teens text every day, half (51%) visit social networking sites daily, and 11% send or receive tweets at least once every day. In fact, more than a third (34%) of teens visit their main social networking site several times a day. One in four (23%) teens are "heavy" social media users, meaning they use at least two different types of social media each and every day.

Now answer this question: In recent years, has the amount of social networking sites available to the public increased or decreased?
greatly increased