I have a following data frame. I need to find count of each type of MNTPCODE for each donor.
CONTID MEDIUMCODE MNTOPCODE CLASCODE EXTRELNO CONTDIREC CONTDATE
000405402 CI CTS CT 0000020 O 1994-05-09
000430904 CI CTS CT 0000020 O 1994-06-14
000592732 CI CTS CT 0000020 O 1994-10-21