i have some data in a sheet.

i want to get a pie chart from that data.

the data is detail in nature

i.e.
type data date blablabla
start something 12/21/12........
start something 12/21/13.........
finish something 12/21/13.........
doing something 11/11/12.........

need to create pie chart to show population demographics
i.e. pie with three pieces two quarters:finish and doing
and 1 half:something. how do i do this?