I'm trying to creating charts showing reading ages of school pupils in several classes. They're in the format yy.mm, so 7.02 is 7 years 2 months, 13.11 is 13 years and 11 months etc. Is there a way to persuade Excel 2010 that the sequence goes 7.00, 7.01, 7.02 ... 7.10, 7.11, 8.00 without it leaving a gap from 7.12 to 7.99?

Sorry if this has already been answered: I did search but couldn't find it.