Dividing Current Months Count by Previous Months Count for a Monthly Graph

[Vroom_Master3]

I am tracking passing scores over time. The data comes in randomly throughout the month. 
So I have to divide the current months count of passing grades by the count of last months passing grades. This should come out to a monthly bar graph showing the "Sustainment" Percentage. 
Here is some example data:

1-Jan	72
7-Jan	80
13-Jan	84
30-Jan	52
3-Feb	75
4-Feb	82
16-Feb	86
20-Feb	86
25-Feb	88
1-Mar	70
4-Mar	82
6-Mar	88
19-Mar	84
21-Mar	75

My problem is that measures filter on monthly graphs very distinctly, and I'm having problems referencing the previous months. The best I hav ever gotten was showing the current month versus the previous month, but no showing any other months. Sadly, i don't have those measures anymore, but I do have what the graph should look. Granted this is a different graph entirely and not this specific data set. 

Thanks for the help. 

[v-xuxinyi-msft]

Hi @Vroom_Master3 

Thanks for the reply from @ryan_mayu , please allow me to provide another insight:

1. Create a calculated column

Month = MONTH([Date])

2. Create several measures as follow

current = CALCULATE(COUNT('Table'[grades]),  ALL('Table'), 'Table'[grades] >= 60, 'Table'[Month] =  MAX([Month]))

Max = 
VAR _maxMonth = MAXX(ALL('Table'), [Month])
VAR _max = CALCULATE(COUNT('Table'[grades]),  ALL('Table'), 'Table'[grades] >= 60, 'Table'[Month] =  _maxMonth)
RETURN
_max

divide = DIVIDE([Max], [current])

Result:

Best Regards,
Yulia Xu

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Vroom_Master3]

This is correct, but only partly. I might be able to make it the rest of the way given this, but your data is offset by a month. Given three months of data you shouldnt be able to calculate 1 month. Its:
'This Months passing grades' / ' Last months passing grades'  
Given this, January should have no data. Your solution calculates as a month versus next month, and because of this, Assigns a 100% to the most recent month

The output in the real data.  Given my data runs Feb-April not Jan-March

[v-xuxinyi-msft]

Hi @Vroom_Master3 

Please check if @ryan_mayu answer meets your needs.

Best Regards,
Yulia Xu

[ryan_mayu · Accepted solution]

@Vroom_Master3 

pls check if this is what you want

create a date table and create measures

pls see the attachment below