Percentage sum for rolling 12 months

[Anonymous]

Hi All,

Hope someone can me with this task please.

Employee = COUNTROWS ( factTable )

Starters = CALCULATE ( [Employee], USERELATIONSHIP ( factTable[StartDateKey, Date[DateKey ) )

After adding the above 2 measures to a table...

Year	Month	Starters	Employees
2017	Jun	27	840
2017	Jul	32	798
2017	Aug	45	825
2017	Sep	110	798
2017	Oct	67	987
2017	Nov	37	798
2017	Dec	47	679
2018	Jan	144	790
2018	Feb	64	810
2018	Mar	32	904
2018	Apr	94	802
2018	May	140	916
2018	Jun	160	789
2018	Jul	158	910
2018	Aug	96	844
2018	Sep	160	828
2018	Oct	144	844
2018	Nov	96	844
2018	Dec	48	844
2019	Jan	80	844
2019	Feb	32	815
2019	Mar	16	844
2019	Apr	32	828
2019	May	48	844
2019	Jun	32	844
2019	Jul	80	844

and I want to get the SUM of percentages of (starters / employees) for the last 12 months on any given month selected from a slicer on the report. The result should look something like this but the Rolling 12 months % sum will be displayed in a card on the report, not in a table like this.

year	month	starters	employees	% starters	Rolling 12 months % sum
2017	Jun	27	840	3.21%
2017	Jul	32	798	4.01%
2017	Aug	45	825	5.45%
2017	Sep	110	798	13.78%
2017	Oct	67	987	6.79%
2017	Nov	37	798	4.64%
2017	Dec	47	679	6.92%
2018	Jan	144	790	18.23%
2018	Feb	64	810	7.90%
2018	Mar	32	904	3.54%
2018	Apr	94	802	11.72%
2018	May	140	916	15.28%
2018	Jun	160	789	20.28%
2018	Jul	158	910	17.36%	131.90%
2018	Aug	96	844	11.37%
2018	Sep	160	828	19.32%
2018	Oct	144	844	17.06%
2018	Nov	96	844	11.37%
2018	Dec	48	844	5.69%
2019	Jan	80	844	9.48%
2019	Feb	32	815	3.93%
2019	Mar	16	844	1.90%
2019	Apr	32	828	3.86%
2019	May	48	844	5.69%
2019	Jun	32	844	3.79%
2019	Jul	80	844	9.48%	102.94%

Thank you.