The number of persons visiting an exhibition daily (in hundreds) in the month of September are as follows:
11, 12. 13, 14, 23, 17, 13, 17, 21, 13, 21, 23, 13, 17, 21, 19, 21, 13, 19, 21, 17, 19, 19, 21, 21, 19, 21, 19, 11, 19.
Prepare a frequency table for the above data.