For displaying percentages, take a look at this blog post: https://blogs.oracle.com/xmlpublisher/entry/working_the_chart_percentages
Take a look at the demo library and look for charts: http://www.oracle.com/technetwork/middleware/bi-publisher/learnmore/demo-library-toc-173301.html
Take a look at this for some other charting posts: https://blogs.oracle.com/xmlpublisher/category/Oracle/Templates/RTF/Charting
This will require modification to the chart code unless you can bring in the values via modification to the sql.
If you want to make modifications to the chart code, make sure you make a copy of the RTF template and then change the chart code for Label as:
<Label><xsl:value-of select="substring(current-group()/DATE,12,5)" /></Label>
You make the change in the Advanced Tab of the Chart in Word 2010 or look for the code under Size in previous versions... Look for the tag <Label>