Calculating minimum of data at load script

[Aspiring_Developer]

Hello everyone,

Please help me with the below data set:-

All the fields are coming from backend:-

My requirement is:

if minimum of Average hourly Rate f(considering all Year) =0, '' , Min(Average Hourly Rate)

I can find the minimum Average Hourly Rate but don't know how to do it for each year like take the minimum values for all years and then compare it if it is equal to 0 or else.

I want to show this in chart as a measure .

Please Please help 

Thanks

[PrashantSangle]

can you post expected output w.r.t. input..