I know. Annoying, isn't it, that you can't use a variable in the TOP clause...you have to use sp_executesql:

DECLARE @n INT

DECALRE @sql NVARCHAR(2000)

SET @n = 76

SET @sql = N'select top 1 salary from (select top ' + @n + ' employeeId from employee

order by salary asc) a

order by salary desc'

EXEC sp_executesql(@sql)

Cheers.