The number of books read by students in a summer reading program is summarized in a box plot. The five-number summary for the data is: Minimum = 2 books, First Quartile (Q1) = 5 books, Median = 8 books, Third Quartile (Q3) = 12 books, Maximum = 18 books. Based on this box plot, what percentage of students read 5 books or more?