How to calculate Running Totals using Power Query in Power BI

How to calculate Cumulative Totals using M-Query in Power BI
Scenario:
Suppose we have a Sample Dataset as follows:

Based on above Data, we need to calculate the Running Totals for Qnty_Sold by Prod_Segment

We can achieve this Scenario using the following M-Query:

let

    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("hZJPawIxEMW/iuxZMH8mk+RYS60teClCD+Ih3Q0aus1KVks/frPLZkGD6+klkN+8zLzZ7Qq6YAtGGCnmhWAMIOrW1vbXta7x8fJS2/IcGu/Ktrv5Q218FU8oi/28w1XCOQeuoq5NqFz7PcEKOrCjNddKYNSP5nK2IUNXwfjSxgPgQOpEMkb0lOuIIgwoHVGKMIW++cqZqJoPJE8kgqQT300gkAGEBGpJuIz6fDSu41aX4N35EuzVfBTLOAqUR13a6oYa+6MJwjFPQqAz25qv2t7DeMpRJExx7LPIvVJfPFnJxAAQKe5YJUpmqTPEPrvc6d2cTLd9iNkk4pbhHadEgchGEY1U37arDt3TdfNjZ0+nU+26OVyvJ81WWwymn6Y9On+YbUwZ9WEdvK2jQWsWdeP+bJi9Buerfn3yKmM+Qt32IonqY31cJM1DxYb2/w==", BinaryEncoding.Base64), Compression.Deflate)), 

let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Order_Date = _t, Order_Id = _t, Prod_Name = _t, Prod_Segment = _t, Country = _t, Qnty_Sold = _t]

    ),

ChangeType =  Table.TransformColumnTypes(Source,{{"Order_Date", type date}, {"Order_Id", Int64.Type}, {"Prod_Name", type text}, {"Prod_Segment", type text}, {"Country", type text}, {"Qnty_Sold", Int64.Type}}),

    

Add_Index = Table.AddIndexColumn(ChangeType, "Index_No", 1, 1, Int64.Type),

/* Running Total Sales*/

Run_Sales = Table.AddColumn(Add_Index, "RT_Sales", 

        each List.Sum(

                List.FirstN(  

                    Add_Index[Qnty_Sold],

                    [Index_No]

                    )

                )   

            ),

/* Running Total Sales by Product Segment */

Seg_Run_Sales = Table.AddColumn(Run_Sales, "Segment_RT_Sales", 

        (OutTable) => 

        List.Sum(

            Table.SelectRows(Add_Index, 

                (InTable) => InTable[Index_No] <= OutTable[Index_No]

                and 

                InTable[Prod_Segment] = OutTable[Prod_Segment]

                )

            [Qnty_Sold]

            )

        )

in

    Seg_Run_Sales

Result:

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Thanks, TAMATAM ; Business Intelligence & Analytics Professional

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