Jerry has taken a random sample of students and determined the number of electives that each student in his sample took last year. There were 19 students in the sample. Here is the data on the number of electives the 19 students took: 6, 6, 8, 7, 7, 7, 8, 9, 10, 8, 7, 6, 9, 6, 8, 7, 9, 7, 10. The mean of this sample data is 7.63. What is the sample proportion of students who took fewer than the mean number of electives?