stop using dynamic sql

Hi,
The following stored procedure (SP) is using a dynamic sql to build the query.
How can this be written using a standard sql. i.e. NOT dynamically being built.
Initially I thought I can have something like the following query but it does not seem to be working for when the where caluse parameters are not passed.
So I ended up using the dynamic sql as it returns the correct data.
Can you see how the SP can be altered please
Thanks

------------------------this query does not return the correct data where the where parameters are not passed.------------
select
*
from
tbl_Management
where

([Year] is null or [Year] = @Year)
AND
(YearPeriod is null or YearPeriod = @YearPeriod)
AND
(AreaCode is null or AreaCode = @AreaCode)

---------------------------------------------------------------

create procedure usp_PatientManagementAdminGet

@Year int = null,
@YearPeriod int = null,
@AreaCode varchar(3) = null

as

declare @sql varchar(1000)

set @sql = 'select'
set @sql = @sql + ' ID'
set @sql = @sql + ' ,AreaCode'
set @sql = @sql + ' ,Year'
set @sql = @sql + ' ,YearPeriod'
set @sql = @sql + ' ,A1=A2+A3'
set @sql = @sql + ' ,A2,A3'
set @sql = @sql + ' ,B1=B2+B3'
set @sql = @sql + ' ,X1=convert(int, ((B2+B3)*1.0/(A2+A3))*100)'
set @sql = @sql + ' from'
set @sql = @sql + ' tbl_Management'
set @sql = @sql + ' where'

if (@Year > 0)
begin
set @sql = @sql + ' [Year] = ' + convert(varchar(4), @Year)
set @sql = @sql + ' AND'
end
if (@YearPeriod > 0)
begin
set @sql = @sql + ' YearPeriod = ' + convert(varchar(2), @YearPeriod)
set @sql = @sql + ' AND'
end
if (@ProgrammeAreaCode is not null)
begin
set @sql = @sql + ' AreaCode = ''' + convert(varchar(3), @AreaCode) + ''''
set @sql = @sql + ' AND'
end

--trim off the last AND...
set @sql = left(@sql, len(@sql) - 3)

exec sp_sqlexec @sql