with t as (
           select  add_months(to_date('01/01/&year','mm/dd/yyyy'),level - 1) dt
             from  dual
             connect by level <= 12
          )
select  to_char(dt,'fmMonth, yyyy') dt,
        trunc((last_day(dt) - trunc(dt,'iw') + 1) / 7) * 6 +
          least(mod(last_day(dt) - trunc(dt,'iw') + 1,7),6) -
least(dt - trunc(dt,'iw'),6) work_days
  from  t
/

select  to_char(dt,'fmMonth, yyyy') dt,
        trunc((last_day(dt) - trunc(dt,'iw') + 1) / 7) * 6 +
          least(mod(last_day(dt) - trunc(dt,'iw') + 1,7),6) -
least(dt - trunc(dt,'iw'),6) work_days
  from  (
           select  add_months(to_date('01/01/&year','mm/dd/yyyy'),level - 1) dt
             from  dual
             connect by level <= 12
          )