The following data gives the number of hours 10 students spent studying and their corresponding grades on their midterm exams.

Hours Spent Studying:
0, 1, 1.5, 2.5, 3, 3.5, 4, 4.5, 5, 5.5
Midterm Grades:
63, 72, 75, 78, 81, 84, 90, 93, 96, 99

Calculate the correlation coefficient, r. Round your answer to three decimal places.