Help With Decimals

Hi all,
This is what I have:
DECLARE @OnTime int
DECLARE @UnControlled int
DECLARE @Volume int
DECLARE @GrossEffect decimal(10,2)
DECLARE @NetEffect decimal(10,2)
DECLARE @WeekEndDate datetime

SET @OnTime = (SELECT COUNT(DataID) FROM tblEDITempARS WHERE OnTimeFlag = 1 AND ARSScanType = 'D' AND ARSType='AN')
SET @UnControlled = (SELECT COUNT(DataID) FROM tblEDITempARS WHERE ControlFlag = 'U' AND ARSScanType = 'D' AND ARSType='AN')
SET @Volume = (SELECT COUNT(DataID) FROM tblEDITempARS WHERE ARSScanType = 'D' AND ARSType='AN')
SET @GrossEffect = (@OnTime/@Volume * 100)
SET @NetEffect = ((@OnTime + @UnControlled)/@Volume * 100)
SET @WeekEndDate = (SELECT DISTINCT WeekEndDate FROM tblEDITempARS)

INSERT INTO tblSummaryData2(ReportType, Volume, NetEffect, GrossEffect, WeekEndDate)
VALUES ('AN',
@Volume,
@NetEffect,
@GrossEffect,
@WeekEndDate)

My numbers are:
OnTime=8089
Uncontrolled=6
Volume=8095

The GrossEffect comes as 0 and the NetEffect=100
AN809501002/21/2004

Why is my GrossEffect = 0??? it should be 99.9