Help On Sql And Logic

Have this table

ID | NAME | Progresscomplete | Release
1 | a | 20% | July
2 | b | 65% | July
3 | c | 33% | July
4 | h | 15% | Sept
5 | i | 30% | Sept
6 | r | 5% | Dec
7 | s | 50% | Dec
8 | t | 15% | Dec
9 | u | 20% | Dec

now I want to create a query that shows the Progresscomplete for each task as a percentage for a Release

so the total progress for each release is
July 300%
Sept 200%
Dec 400%

and the current level of progress for each release is
July 39.33% (118/300*100)
Sept 22.5 % (45/200*100)
Dec 22.5 % (90/400*100)

thus the current level of progress for each task within a release is
1 | a | 16.9% (20/118*100) | July
2 | b | 55% (65/118*100) | July
3 | c | 28% (33/118*100) | July
4 | h | 33% (15/45*100) | Sept
5 | i | 66% (30/45*100) | Sept
6 | r | 5% (5/90*100) | Dec
7 | s | 55% (50/90*100) | Dec
8 | t | 16.6% (15/90*100) | Dec
9 | u | 22% (20/90*100) | Dec

I have queries for the first two not sure about the last also
not sure if i should have the base of the last output be the current level of progress for each release or the total progress for each release

I have tried this for the last output

SELECT ID, NAME, ((Progresscomplete/Count(Progresscomplete))*100) AS currentprogresslevel, Release
FROM TEST_RawData
GROUP BY Release;

but get an error "tried to execute a query that does not include specified expression... as part of an aggregate function.