Calculation of values within same column based on category of another column

[sk007]

I have data like this. I would like to create a new column (Collection_Ratio) calculating the Collection by using this formula:

1-(End/Beginning).  

This is the result that I want to have: 

How can I achieve this? Please don't mind if this is a simple question. I am new to PowerBI. Thanks. 

[Fowmy · Accepted solution]

@sk007 

Create a measure, add Period on a table visual and this measure. Replace table with your table name

Collection Ratio=
DIVIDE (
    CALCULATE ( SUM ( table[collection] ), table[data] = "End" ),
    CALCULATE ( SUM ( table[collection] ), table[data] = "Beginning" )
)