I need some help to gather data out of colomn from an excel file.

(opening test.xls) I need to get out data from colomn C and count out the incidence in colomn I automatically.
Fo example "faulty component " was listed twice in column C so in column I7 it must count 2. If "faulty component" should be relisted again in column C I7 must turn to 3 automatically.
Any help is appreciated!