Basic Information on MarkLogic Collections

I wanted to get some quick information about all of my collections, starting with a list of names and how many documents were in each. This isn't rocket science, but I'll add to this post as the query expands.

(: Set "collection lexicon" to true in the index definition. :)
let $collections := cts:collections() return
<root count="{ fn:count($collections) }">
{
for $collection in $collections
return
  <collection>
    <name> { $collection } </name>
    <size> { fn:count(fn:collection($collection)) } </size>
  </collection>
}
</root>