Charting results from query

Hi all

I need to chart some information from a query and I don't really have any
experience of charts. I will only ever have one record in my datasource
(query called WarrantyPerformance). It shows results of a particular dealer
(dealercode), I have 10 different results and 10 matching variances to plot.
for eg

Cost per Veh 141.07 - Variance = 41%
Claims per Veh 82.16 - Variance = -18%

The National amount is always 100, therefore the variance relates to this. I
want to be able to show a trend somehow and have all the variances over 0
shown in red (ie the cost value is greater than 100). So above the Cost per
Veh would be red whereas the Claims per Veh would be green.

How would I go about achieving this, if it is possible?

Thanks in advance for any help.
Sue