When 'Select All' Parameter ticked all data is not showing - sql

Question

This is a glimpse of what my report look likes, a series of charts, where you can select a country and a date range of either 12 months rolling or 36 months rolling.
The report is working ok in regards to selecting one country and seeing the different data within the 12 or 36 months date range.
The problem comes when I 'Select All' countries. What I want is the totals of all the countries to be represented on the graphs. As you see below, with all countries selected the data on the graph has not changed from the image above.
The Country parameter
This is my stored procedure
ALTER PROCEDURE [name] #Country VARCHAR(max)
,#DateRange VARCHAR(max)
AS
BEGIN
SELECT country
,[yyyy-mm]
,[12Months]
,[36Months]
,[Population]
,[Employed]
FROM (
SELECT CASE [countryID]
WHEN '800002'
THEN 'UK'
WHEN '800003'
THEN 'France'
WHEN '800004'
THEN 'Germany'
ELSE 'N/A'
END AS country
,Convert(CHAR(7), [DateTimeOfCall], 121) "yyyy-mm"
,CASE
WHEN datetimeofcall BETWEEN Dateadd(Month, Datediff(Month, 0, DATEADD(m, - 12, current_timestamp)), 0)
AND Dateadd(Month, Datediff(Month, 0, DATEADD(m, 0, current_timestamp)), 0)
THEN 'y'
ELSE 'n'
END AS [12Months]
,CASE
WHEN datetimeofcall BETWEEN Dateadd(Month, Datediff(Month, 0, DATEADD(m, - 36, current_timestamp)), 0)
AND Dateadd(Month, Datediff(Month, 0, DATEADD(m, 0, current_timestamp)), 0)
THEN 'y'
ELSE 'n'
END AS [36Months]
,sum(CASE
WHEN [CategoryID] = '180003'
AND [CauseID] IN (
'700002'
,'700003'
)
AND [TypeID] = '100002'
AND [PopTypeID] BETWEEN '170002'
AND '170019'
THEN 1
ELSE 0
END) Population
,sum(CASE
WHEN [EmpID] = '210002'
THEN 1
ELSE 0
END) AS Employed
FROM [dbo].[country]
WHERE STATUS = '1'
GROUP BY [countryID]
,Convert(CHAR(7), [DateTimeOfCall], 121)
,CASE
WHEN datetimeofcall BETWEEN Dateadd(Month, Datediff(Month, 0, DATEADD(m, - 12, current_timestamp)), 0)
AND Dateadd(Month, Datediff(Month, 0, DATEADD(m, 0, current_timestamp)), 0)
THEN 'y'
ELSE 'n'
END
,CASE
WHEN datetimeofcall BETWEEN Dateadd(Month, Datediff(Month, 0, DATEADD(m, - 36, current_timestamp)), 0)
AND Dateadd(Month, Datediff(Month, 0, DATEADD(m, 0, current_timestamp)), 0)
THEN 'y'
ELSE 'n'
END
) a
WHERE country in (#country)
AND (
(
#DateRange = 12
AND [12Months] = 'Y'
)
OR (
#DateRange = 36
AND [36Months] = 'Y'
)
)
END
And this is what the output is
country yyyy-mm Population Employed 12months 36months
uk 2016-06 56 43 y y
france 2016-06 40 22 y y
Germany 2016-06 73 32 y y
uk 2015-06 45 10 n y
france 2015-06 30 11 n y
Germany 2015-06 76 56 n y
AND SO ON......
All help appreciated, thank you.