(:
   OBSOLETED!
   date:   23-June-2010
   author: Gary Lewis
   notes:  1. Replaced by freq_inst_by_numYr_v2.xq when the 25 files called distinct_unitids_by_year.xml (1
              file for each year in the time series) were eliminated.
:)

(:
   file:    freq_inst_by_numYr.xq
   date:    24-May-2010
   author:  Gary Lewis
   purpose: Frequency distribution of number of institutions by the number of years that the
            institutions appear in the 25 IPEDS directory data files 1980 - 2008.
   use:     Run program from path location where it resides.
   example: zorba -f -q freq_inst_by_numYr.xq -o freq_inst_by_numYr.xml -z indent=yes
:)

<distribution>
{
let $tmp1 := 
    for $x in (
        fn:doc("../2008/HD2008/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2007/HD2007/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2006/HD2006/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2005/HD2005/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2004/HD2004/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2003/HD2003/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2002/HD2002/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2001/FA2001HD/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../2000/FA2000HD/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1998/IC98hdac/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1997/ic9798_HDR/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1996/ic9697_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1995/ic9596_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1994/IC1994_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1993/IC1993_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1992/IC1992_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1991/IC1991_hdr/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1990/IC90HD/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1989/IC1989_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1988/IC1988_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1987/IC1987_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1986/IC1986_A/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1985/IC1985/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1984/IC1984/distinct_unitids_by_year.xml")/directory/inst/@unitid | 
        fn:doc("../1980/IC1980/distinct_unitids_by_year.xml")/directory/inst/@unitid
        )
   let $cnt := 1
   group by $x
   return <inst unitid="{$x}" count="{sum($cnt)}" />
return 
let $tmp2 :=
    for $y in $tmp1/@count
    let $freq := 1
    group by $y
    order by xs:integer($y) ascending
    return <freq numYrs="{$y}" numInst="{sum($freq)}" />
return $tmp2
}
</distribution>