One in three young people in the U.S. have never had a mentor, yet 55% of young people are more likely to enroll in college when they have one, according to a new study by MENTOR. We at LinkedIn feel that mentorship is incredibly important and these relationships can make a real difference in the lives of underserved youth. We’re asking our members to celebrate and acknowledge their mentors. Simply #ThankYourMentor by @mentioning them in a LinkedIn update with the hashtag. Take…