Unwinding annual cumulative data

[mterry]

I have data sets the I receive quarterly and the information is cumulative, so I'm looking for the most succint way to convert it from cumulative to quarterly data in the form of a new column that subtracts the previous period by country and by category. 

The first table below is how the data appear now, the second is what I would like to add. I think I could unpivot and just subtract, but hoping there is a better way to perform this in the existing format. 

Country	Supply	Date	Annual Cumulative Amount
United States	Computers	3/31/2020	5,000.00
Canada	Computers	3/31/2020	5,000.00
UK	Computers	3/31/2020	5,000.00
United States	Chairs	3/31/2020	6,000.00
Canada	Chairs	3/31/2020	6,000.00
UK	Chairs	3/31/2020	6,000.00
United States	Desk	3/31/2020	7,000.00
Canada	Desk	3/31/2020	7,000.00
UK	Desk	3/31/2020	7,000.00
United States	Monitor	3/31/2020	8,000.00
Canada	Monitor	3/31/2020	8,000.00
UK	Monitor	3/31/2020	8,000.00
United States	Other	3/31/2020	9,000.00
Canada	Other	3/31/2020	10,000.00
UK	Other	3/31/2020	10,000.00
United States	Computers	6/30/2020	10,000.00
Canada	Computers	6/30/2020	12,000.00
UK	Computers	6/30/2020	12,000.00
United States	Chairs	6/30/2020	12,000.00
Canada	Chairs	6/30/2020	14,000.00
UK	Chairs	6/30/2020	14,000.00
United States	Desk	6/30/2020	14,000.00
Canada	Desk	6/30/2020	16,000.00
UK	Desk	6/30/2020	16,000.00
United States	Monitor	6/30/2020	16,000.00
Canada	Monitor	6/30/2020	18,000.00
UK	Monitor	6/30/2020	20,000.00
United States	Other	6/30/2020	20,000.00
Canada	Other	6/30/2020	20,000.00
UK	Other	6/30/2020	24,000.00
United States	Computers	9/30/2020	24,000.00
Canada	Computers	9/30/2020	24,000.00
UK	Computers	9/30/2020	28,000.00
United States	Chairs	9/30/2020	28,000.00
Canada	Chairs	9/30/2020	28,000.00
UK	Chairs	9/30/2020	32,000.00
United States	Desk	9/30/2020	32,000.00
Canada	Desk	9/30/2020	32,000.00
UK	Desk	9/30/2020	36,000.00
United States	Monitor	9/30/2020	40,000.00
Canada	Monitor	9/30/2020	40,000.00
UK	Monitor	9/30/2020	40,000.00
United States	Other	9/30/2020	48,000.00
Canada	Other	9/30/2020	48,000.00
UK	Other	9/30/2020	48,000.00

What I would like:

Country	Supply	Date	Cumulative Amount	Amount Per Period
United States	Computers	3/31/2020	5,000.00	5,000.00
Canada	Computers	3/31/2020	5,000.00	5,000.00
UK	Computers	3/31/2020	5,000.00	5,000.00
United States	Chairs	3/31/2020	6,000.00	6,000.00
Canada	Chairs	3/31/2020	6,000.00	6,000.00
UK	Chairs	3/31/2020	6,000.00	6,000.00
United States	Desk	3/31/2020	7,000.00	7,000.00
Canada	Desk	3/31/2020	7,000.00	7,000.00
UK	Desk	3/31/2020	7,000.00	7,000.00
United States	Monitor	3/31/2020	8,000.00	8,000.00
Canada	Monitor	3/31/2020	8,000.00	8,000.00
UK	Monitor	3/31/2020	8,000.00	8,000.00
United States	Other	3/31/2020	9,000.00	9,000.00
Canada	Other	3/31/2020	9,000.00	9,000.00
UK	Other	3/31/2020	9,000.00	9,000.00
United States	Computers	6/30/2020	10,000.00	5,000.00
Canada	Computers	6/30/2020	12,000.00	7,000.00
UK	Computers	6/30/2020	12,000.00	7,000.00
United States	Chairs	6/30/2020	12,000.00	6,000.00
Canada	Chairs	6/30/2020	14,000.00	8,000.00
UK	Chairs	6/30/2020	14,000.00	8,000.00
United States	Desk	6/30/2020	14,000.00	7,000.00
Canada	Desk	6/30/2020	16,000.00	9,000.00
UK	Desk	6/30/2020	16,000.00	9,000.00
United States	Monitor	6/30/2020	16,000.00	8,000.00
Canada	Monitor	6/30/2020	18,000.00	10,000.00
UK	Monitor	6/30/2020	18,000.00	10,000.00
United States	Other	6/30/2020	18,000.00	9,000.00
Canada	Other	6/30/2020	20,000.00	11,000.00
UK	Other	6/30/2020	24,000.00	15,000.00
United States	Computers	9/30/2020	20,000.00	10,000.00
Canada	Computers	9/30/2020	20,000.00	8,000.00
UK	Computers	9/30/2020	20,000.00	8,000.00
United States	Chairs	9/30/2020	24,000.00	12,000.00
Canada	Chairs	9/30/2020	24,000.00	10,000.00
UK	Chairs	9/30/2020	24,000.00	10,000.00
United States	Desk	9/30/2020	28,000.00	14,000.00
Canada	Desk	9/30/2020	28,000.00	12,000.00
UK	Desk	9/30/2020	28,000.00	12,000.00
United States	Monitor	9/30/2020	32,000.00	16,000.00
Canada	Monitor	9/30/2020	32,000.00	14,000.00
UK	Monitor	9/30/2020	32,000.00	14,000.00
United States	Other	9/30/2020	36,000.00	18,000.00
Canada	Other	9/30/2020	36,000.00	16,000.00
UK	Other	9/30/2020	36,000.00	12,000.00

[mterry]

I've ran into a bug with the above that seems to be a common occurrence in BI, but I can't work out. The formual works properly for displaying a total amount broken out by each quarter. However, if I include all the quarters for a year in a matrix, then the total showing in the matrix is way off even though the subtotals by quarter are accurate. If I display the same data in a waterfall visual, all data is accurate, including the total. Unfortunately I'm unable to share the data, and I realize that makes my question difficult, but does anyone have suggestions I could use so that totals are wrong when I use the above measure? Is there a way to replicate this in Power Query or with a calculated column? 

[amitchandak]

@mterry , refer if this can help

Distributing/Allocating the Yearly Target(Convert to Daily Target): Measure ( Daily/YTD): Magic of CLOSINGBALANCEYEAR With TOTALYTD/DATESYTD: https://community.powerbi.com/t5/Community-Blog/Power-BI-Distributing-Allocating-the-Yearly-Target-C...

[mterry]

I read through that article and I don't think it quite gets me what I want. I think I got there with the below, every quarter subtracts the cumulative amount from the previous quarter unless it's Q1, effectively limiting the calcs to be within the same year. 

Quarterly Spend = IF(QUARTER(MAX(SAP_quarterly[Date])) = 1, SUM(SAP_quarterly[**bleep**. Ann. Spend]), SUM(SAP_quarterly[**bleep**. Ann. Spend])-CALCULATE(SUM(SAP_quarterly[**bleep**. Ann. Spend]), PREVIOUSQUARTER(SAP_quarterly[Date])))