I need to be able to create charts from data. However the data is in the form;

4c
3a
3b
3c
2a
2b
2c

They are childrens grades in school, wher 4c is the highest then 3a etc.
All the data already exists in excel, people need to be able to read the data in the form shown, but I think that giving these a value will aid manipulation and graphing of the data?

Can this be done so that anytime the data, say 4c is input it is assigned a value 100, then 3a = 90, 3b = 80 etc...

Any (basic!) help appreciated