Depending on the version of Cognos, and how you've structured the query, I can offer you a few possible solutions.
It looks like this is a dimensional query, are you using filters or slicers?
The easiest solution would be to simply place a prompt macro with a default selection into the slicer.
For example
#prompt('Year','memberuniquename','[CurrentYearMember]')#
If the user runs the report without selecting a year, it will simply default to [CurrentYearMember].