<ul>
  <li>There are <$text text={{{ [tag[Contact]count[]] }}}/> people in this wiki.</li>
  <li>There are <$text text={{{ [tag[Meeting]links[]count[]] }}}/> tiddlers linked from meetings.</li>
  <$let totalTiddlers={{{ [!is[system]count[]] }}}>
    <li><$text text={{{ [tag[Contact]count[]divide<totalTiddlers>multiply[100]precision[3]] }}}/>% of all non-system tiddlers in the wiki are contacts.</li>
  </$let>
</ul>

Note the use of an HTML list. If we tried to do the list in pure wikitext with *, we would have been unable to place the third bullet point in the same list as the first two, as the $let widget coming in between causes TiddlyWiki to forget that a list was in progress. We could have put the $let widget around the entire list, but then it would have been harder to understand what we were doing since the first part of the calculation would have been physically separated from the second part. Always prioritize readability in your wikitext!