(:
   file:    verify_pop_all_years.xq
   date:    29-July-2010
   author:  Gary Lewis
   purpose: Verify counts from pop_all_years.xml versus Table 265 of the NCES Digest of Education Statistics 2009.
   usage:   Run program from path where it is located.
   example: zorba -f -q verify_pop_all_years.xq -z indent=yes
:)

<results>
{
for $i in fn:doc("pop_all_years.xml")/population/survey
let $year := $i/@year,
    $j := $i/inst,
    $unitid := $j/@unitid
group by $year
order by $year descending
return <pop year="{$year}" numInst="{count($unitid)}" />
}
</results>