sql - Trouble making a running sum in Access query -

i'm stuck trying running sum work in access query. i've been playing around various dsum expressions, have resulted in errors. basically, have 2 columns, 1 year, 1 count of parts year, , third running sum of part count on years.

my sql first 2 columns looks this:

    select datepart("yyyy",[eol]) ayear, count(equipmentquery.equipment) equipcount     equipmentquery     group datepart("yyyy",[eol])     order datepart("yyyy",[eol]); 

any suggestions on how third column work running sum? help!

if create report, there property calculate running sum.

if prefer query, can use subquery calculate running sum:

select  datepart("yyyy",[eol]) ayear ,       count(eq1.equipment) equipcount ,       (         select  count(eq2.equipment)            equipmentquery eq2           datepart("yyyy",eq2.[eol]) <= datepart("yyyy",eq1.[eol])         ) runningsuma    equipmentquery eq1 group          datepart("yyyy",[eol]) order          datepart("yyyy",[eol]);