Attrition Formula

Hi Dhavales ,

Based on my understanding,Annual %= Sum(past 12 months monthly%) should be a summarize of the pasting 12 months,I dont understand why from Jun 19 to Nov 19,the result returns 0?And why the value in Dec 19 is higher than the later values.

I made a sample .pbix file to calculate the total value if I didnt understand wrong,pls see below:

Create a measure as below:

Annual Attrition% = 
var _mindate=CALCULATE(MAX('Table'[Date]),DATEADD('Table'[Date],-12,MONTH))
Return
SUMX(FILTER(ALL('Table'),'Table'[Date]>=_mindate&&'Table'[Date]<=MAX('Table'[Date])),'Table'[Monthly %])

And you will see:

For the related .pbix file,pls click here.