DECLARE @anoy int
    SET @anoy = YEAR(GETDATE())
    DECLARE @mesy int
    SET @mesy = YEAR(GETDATE()) - 1

    SELECT SUM(total) total
    from (
        select sum(workOrder) as total from workOrder where workType = '02' and year(workOrderDate) = @mesy
    union all
    select sum(workOrder) as total from workOrder where workType= 'corretiva' and year(workOrderDate)= @mesy
    ) s;

    WITH subresults AS
                ( SELECT MES = MONTH(workOrderDate),
                preventiva = (SUM(CASE WHEN WorkType = '02' AND workOrderDescription = 'preventiva' THEN 1.0 ELSE 0 END )),
                corretivas = (SUM(CASE WHEN workOrderDescription = 'CORRETIVA' THEN 1 ELSE 0 END)),
                total = SUM(CASE WHEN WorkType = '02' AND workOrderDescription = 'preventiva' THEN 1.0
                ELSE 0 END + CASE WHEN workOrderDescription = 'CORRETIVA' THEN 1 ELSE 0 END )
                FROM WorkOrder WHERE
                YEAR(workorderDate) = @mesy
                GROUP BY MONTH(workOrderDate))
                SELECT s.MES ,s.preventiva ,s.corretivas ,s.total,
                preventivasPct = CASE WHEN s.total <> 0 THEN(s.preventiva / s.total) * 100.0 ELSE NULL END,
                corretivasPct = CASE WHEN s.total <> 0 THEN(s.corretivas / s.total) * 100.0 ELSE NULL END
                FROM subresults s