stacked bar chart
 

I have a chart that has dates, (month,year) as the y axis from 1/2003 thru
4/2006. The x axis is 3 of 15 (top 3) of a series of data. My question is
can the bars be displayed so that the highest valued data is on the
top/bottom of the bar and vice versa. I can't enter the data differently
because each month it is not always the same top 3 and I need to keep the
color coding.

Thanks.