You can have the wiki generate a chart based on tabular data.

Example

The following code inserted in your wiki page:

{chart:title=Pitfalls}
|| ||Quicksand||Alligators||
|# affected|3|4|
{chart}

Will produce the following output:

Want to do more pie chart formatting? See the following links:
More on Pie Charts
Pie Charts with Data Labels

Example 2

Here's a more complex one - the following code:

{chart:type=bar|stacked=true|bgColor=#F9F9F7|3D=true|opacity=50}
|| ||Trout||Herring||Pike||
||John|15|26|41|
||David|21|8|29|
{chart}

Will produce the following output:

Many other formatting options are documented in the notation guide