Selecting Time averages




How to select the yearly average value of a line item from a module that is dimensioned by time (monthly), for the current year, in another module that is not dimensioned by time? Please note, I wish to make the formula dynamic and not use static values like TIME.FY19 


I have a "Shipments" module that is having monthly scale, time dimension. Line item "ShipmentRatio %" is a percent formatted metric.


I have another module called "Yearly Assumptions", which is not dimensioned by time. 


In the Year Assumptions module, I wish to calculate a line item as follows:


CurrentYrAvgRatio = Shipments.ShipmentRatio %[SELECT: TIME.'FY19']

Please note that ShipmentRatio % Summary and Time Summary methods have been set to "Average"


I don't want to hardcode 'FY19'. 


Using Shipments.ShipmentRatio %[SELECT: TIME.'Current Period'] is not helping as it is giving me the first MONTH's value from 2019, instead of FY19 average.


How can this be resolved?