"According to Yahoo, 40% of searches are simply searching for what you saw before."

https://www.seenbefore.com/pages/faq#currently_do

They should link to the study.

If I remember correctly, this was the result of some research done by a startup. Or was it Google? I couldn't tell you because this service didn't exist back when I read that article

https://duckduckgo.com/?q=random+number+between+1+and+100 :P